feat(a380x/rmp): improve api for hardware users and add standby mode handling

[tracernz]

Fixes #8951
Fixes #9209
Fixes #10015

Summary of Changes

• Makes the RMP frequencies and modes, RMP states, and all COM K event handling for hardware/API users available.
• Adds basic handling for the standby frequency modes on VHF3.
• Fixes the ATC frequency being de-tuned on runway spawn in MSFS2024.
• Included are some radio util improvements that are useful for the A32NX in future as well.

Screenshots (if necessary)

References

Additional context

Discord username (if different from GitHub):

Testing instructions

Ensure VHF tuning still works properly on the RMPs. Check that the active frequencies are actually tuned by using the SimVar watcher from the MSFS SDK to watch COM ACTIVE FREQUENCY simvars.

Need to come up with some tests for the API stuff...

How to download the PR for QA

Every new commit to this PR will cause new A32NX and A380X artifacts to be created, built, and uploaded.

1. Make sure you are signed in to GitHub
2. Click on the Checks tab on the PR
3. On the left side, find and click on the PR Build tab
4. Click on either flybywire-aircraft-a320-neo, flybywire-aircraft-a380-842 (4K) or flybywire-aircraft-a380-842 (8K) download link at the bottom of the page

[Benjozork]

Waiting for futher details in testing instructions to send to QA.