split initialization of sonic_platform to a per-daemon basis

[stephenxs]

- What I did
split sonic_platform initialization to a per-daemon basis to save the startup time of daemons
make Mellanox new platform api able to be installed on host so that reboot cause can be handled on it.

- How I did it

1. modify makefiles so that the following modules are installed on host:
   • sonic_platform, which handles reboot cause
   • sonic_daemon_base, on which sonic_platform depends
2. remove unnecessary dependencies of sonic_platform on host
   • implement platform.py
   • add an added argument to sonic_platform.platform.Platform's constructor, as following:
     Platform.__init__(self, daemon = None)
     • [TBD] the base class sonic_platform_base.platform_base.PlatformBase.init should be updated accordingly
   • Platform's constructor loads and initializes only the functionalities on a per-daemon basis, i.e. only functionalities required by the daemon are initialized for it.
   • define initializers for each components belonging the chassis and remove them out of the chassis's constructor so that they can be called only when needed. currently the following initializers defined:
     • initialize_psu
     • initialize_watchdog
     • initialize_fan
     • initialize_sfp
     • initialize_eeprom
     • initialize_components_list

- How to verify it
load chassis on host and check whether reboot-cause and watchdog can be well handled.
load chassis on pmon docker and check whether other components can be well handled.
run process-reboot-cause and check whether the correct reboot cause can be parsed.

- Description for the changelog

- A picture of a cute animal (not mandatory but encouraged)

[stephenxs]

I'm going to split this PR into 3 which contain the following logic and then close it.

1. installing vendor-specific sonic_platform on the host:
   • make file rules which contains the logic of making it and installing it.
   • remove unnecessary dependencies which can block sonic_platform from installing on the host.
2. fix the sonic_daemon_base's issue which reports error when destructing sonic_daemon_base.
3. mellanox specific part:
   • split initializers of variant categories of devices so that unnecessary dependencies can be avoided
   • improve reboot-cause-handling logic