Fix #169, make separate targets for PSP

[jphickey]

Describe the contribution
Restructure code to make more amicable for rebuilding in a unit test environment. No major changes, primarily just shifting code between locations/headers to support unit testing.

Fixes #169

Testing performed
Build and sanity check CFE on RTEMS and Linux
Run all unit tests and confirm passing.

Expected behavior changes
No impact to behavior.

System(s) tested on
Ubuntu 20.04
RTEMS 4.11.3 via QEMU/pc686

Additional context
Makes the code structure better for unit testing.

Contributor Info - All information REQUIRED for consideration of pull request
Joseph Hickey, Vantage Systems, Inc.

[astrogeco]

CCB 2020-06-17: @skliper and @jphickey will have a splinter to discuss design approach

[astrogeco]

@skliper and @jphickey what's the status on this?

[jphickey]

So far we haven't had a splinter meeting about this but I'm happy to do so any time. The unique case here is that it is building the UT for potentially other targets than what the FSW is built for (like OSAL coverage) but unlike OSAL coverage it is building it as one unit, not separate units. So IMO this use-case made sense to use the same CMakeLists.txt subdir files create the same targets but with a different name.

Ideally in a future version I'd like to pursue the concept of a fully-modular PSP, where the PSP is just an assembly of extra modules linked into cfe core. Then each module can get its own separate coverage test. But in the meantime I think this works for the current PSP architecture.

[skliper]

I'm good with it, just needed to look again. I also really like the direction of treating PSP as an assembly of extra modules.

[astrogeco]

I'm good with it, just needed to look again. I also really like the direction of treating PSP as an assembly of extra modules.

So should I add it to IC-20200617?

[skliper]

I'm good with it, just needed to look again. I also really like the direction of treating PSP as an assembly of extra modules.

So should I add it to IC-20200617?

Yes please! The sooner the better.