Merge rdsn and Pegasus

[acelyc111]

Although rdsn and Pegasus have been merged to one repo, there are still many work left to do:

• unify th clang-format tools
• remove run.sh in rdsn
• unify the workflows
• unify the CMakelists.txt
• Unify build and test shell scripts to run.sh
• Move some common files out of rdsn directory
• reduce rebuilding time cost
• Unify the cmake of rdsn and pegasus
• move files in 'include' dir of rdsn to the src pf rdsn
• refactor(rdsn): flatten source code directory by moving files from 'src/rdsn/src/' to 'src/'

[acelyc111]

Refactor directories

After the xiaomi/rdsn project has been merged into the Pegasus project, the rdsn source code directory structure is kept as before in the original repository. But it's just a temporary status, we are planning to integrate the two projects closer in the long-term plan.

The following things I'm going to do is moving source code directories from src/rdsn/src/* to src/*, for example, src/rdsn/src/runtime/api_task.h will be moved to src/runtime/api_task.h, this change will make the source structure more simple and easier to understand and accept by more new comer of Pegasus.

Of course, it's just one step of the whole refactory plan, the src/rdsn/include/* files have been moved to the places where they are more related to by pull request [1]. And there will be more refactor pull requests to modularize the source files in the future.

However, this change will influence hundreds of files, their paths will be changed, even though there are no functional changes. This change is presented by this [2] pull request.

Keep in mind that this is not the final view of the structure, we will do more small adjusticement in the future.

Directories in src before this refactor:

.
├── base
│   └── test
├── client_lib
├── geo
│   ├── bench
│   ├── lib
│   └── test
├── include
│   ├── pegasus
│   └── rrdb
├── rdsn
│   └── src
│       ├── aio
│       │   └── test
│       ├── block_service
│       │   ├── fds
│       │   ├── hdfs
│       │   ├── local
│       │   └── test
│       ├── client
│       ├── common
│       │   ├── serialization_helper
│       │   └── test
│       ├── failure_detector
│       │   └── test
│       ├── http
│       │   └── test
│       ├── meta
│       │   ├── duplication
│       │   └── test
│       │       ├── balancer_simulator
│       │       ├── meta_state
│       │       └── misc
│       ├── nfs
│       │   └── test
│       ├── perf_counter
│       │   └── test
│       ├── remote_cmd
│       ├── replica
│       │   ├── backup
│       │   │   └── test
│       │   ├── bulk_load
│       │   │   └── test
│       │   ├── duplication
│       │   │   └── test
│       │   ├── split
│       │   │   └── test
│       │   ├── storage
│       │   │   └── simple_kv
│       │   │       └── test
│       │   └── test
│       ├── runtime
│       │   ├── rpc
│       │   ├── security
│       │   ├── task
│       │   └── test
│       ├── tools
│       ├── utils
│       │   ├── absl
│       │   │   ├── base
│       │   │   │   └── internal
│       │   │   └── utility
│       │   ├── hpc_locks
│       │   ├── long_adder_bench
│       │   └── test
│       │       └── nth_element_bench
│       └── zookeeper
│           └── test
├── redis_protocol
│   ├── proxy
│   ├── proxy_lib
│   └── proxy_ut
├── reporter
├── sample
├── server
│   └── test
├── shell
│   ├── commands
│   ├── linenoise
│   └── sds
└── test
    ├── bench_test
    ├── function_test
    │   ├── backup_restore_test
    │   ├── base_api_test
    │   ├── bulk_load_test
    │   ├── detect_hotspot_test
    │   ├── partition_split_test
    │   ├── recovery_test
    │   ├── restore_test
    │   ├── throttle_test
    │   └── utils
    ├── kill_test
    └── pressure_test

Directories in src after this refactor:

.
├── aio
│   └── test
├── base
│   └── test
├── block_service
│   ├── fds
│   ├── hdfs
│   ├── local
│   └── test
├── client
├── client_lib
├── common
│   ├── serialization_helper
│   └── test
├── failure_detector
│   └── test
├── geo
│   ├── bench
│   ├── lib
│   └── test
├── http
│   └── test
├── include
│   ├── pegasus
│   └── rrdb
├── meta
│   ├── duplication
│   └── test
│       ├── balancer_simulator
│       ├── meta_state
│       └── misc
├── nfs
│   └── test
├── perf_counter
│   └── test
├── redis_protocol
│   ├── proxy
│   ├── proxy_lib
│   └── proxy_ut
├── remote_cmd
├── replica
│   ├── backup
│   │   └── test
│   ├── bulk_load
│   │   └── test
│   ├── duplication
│   │   └── test
│   ├── split
│   │   └── test
│   ├── storage
│   │   └── simple_kv
│   │       └── test
│   └── test
├── reporter
├── runtime
│   ├── rpc
│   ├── security
│   ├── task
│   └── test
├── sample
├── server
│   └── test
├── shell
│   ├── commands
│   ├── linenoise
│   └── sds
├── test
│   ├── bench_test
│   ├── function_test
│   │   ├── backup_restore_test
│   │   ├── base_api_test
│   │   ├── bulk_load_test
│   │   ├── detect_hotspot_test
│   │   ├── partition_split_test
│   │   ├── recovery_test
│   │   ├── restore_test
│   │   ├── throttle_test
│   │   └── utils
│   ├── kill_test
│   └── pressure_test
├── tools
├── utils
│   ├── absl
│   │   ├── base
│   │   │   └── internal
│   │   └── utility
│   ├── hpc_locks
│   ├── long_adder_bench
│   └── test
│       └── nth_element_bench
└── zookeeper
    └── test

1. refactor(rdsn): remove 'include' directory in rdsn #1189
2. refactor(rdsn): flatten source code directory by moving files from 'src/rdsn/src/*' to 'src/*' #1190

[acelyc111]

Now the "merge" work has been completed almostly, the following work is refactory the code.