FPP v2.3.0a1

[bocchino]

This PR integrates FPP v2.3.0a1. It also makes the following changes to F Prime:

1. In docs, add documentation for state machines.
2. In FppTest, add tests for covering FPP state machines and related code generation.
3. Improve const correctness in the framework.
4. Update models to escape new keywords with $ as necessary.

Reviewing Notes

Notes and status from the in-person review on 11/20/24 are here: nasa/fpp#508 (comment).

To review code coverage on the tests, you can run fprime-util check --coverage --all-sources in the following directories:

FppTest/state_machine/internal/initial
FppTest/state_machine/internal/state
FppTest/state_machine/internal/coverage
FppTest/state_machine/internal_instance/initial
FppTest/state_machine/internal_instance/state
FppTest/state_machine/internal_instance/coverage

Code coverage is around 90-100% except in fprime/FppTest/state_machine/internal_instance/initial, where the coverage of the auto-generated component code is about 40%. This is because of the modular test design: these tests don't send signals to the state machines; only state machine initialization is tested. The code for sending signals is exercised in the other test suites.

[LeStarch]

I looked at the structure of FppTest and reviewed the files outside of FppTest. Approved.