feat: enable Companion simulator to switch UI language at runtime

[philmoz]

Testing language translations is slow and tedious requiring rebuilding the simulator libraries multiple times.
This PR enables the simulator to load all language translations and fonts at startup allowing the UI language to be switched at will, while running the simulator.

Primary goals:

• Minimise the code changes required to the current code base.
• Normal firmware builds should be functionally equivalent with little to no change in the radio operation, performance, firmware size or RAM usage.

The UI language is changed in the simulator using the existing 'Voice Language' setting.

In addition this can be compiled and run on some current radios:

• B&W radios with 1MB of FLASH. Tested on GX12 and BumbleBee.
• Color radios with 8MB of FLASH and at least 8MB of RAM. Tested on ST16, TX15 and T15Pro.

When used on compatible B&W radios the flash size is increased by ~300K, leaving ~200K free. RAM usage is increased by a few hundred bytes.
On compatible color radios the flash size increases by ~1.9MB. RAM usage increases with ~2.3MB free at startup (down from ~3.9MB).

To build for a radio add -DALL_LANGUAGES=YES to the cmake configuration.

TODO:

• Generate the sim_string_list.h file in the build process (dependent on string_list.h). Currently created using 'm4' preprocessor and the simstr.m4 file.

[philmoz]

Also works in the standalone simulator.

[raphaelcoeffic]

Applying the patches from #6561 seems to help regain some SDRAM already:

• without the patch:

❯ arm-none-eabi-nm -n -S build/firmware.elf | grep _heap_
c03aab54 B _heap_start
c0800000 A _heap_end

That's ~4.3MB heap.

• with the patch from feat: flash only assets #6561:

❯ arm-none-eabi-nm -n -S build/firmware.elf | grep _heap_
c0269cc4 B _heap_start
c0800000 A _heap_end

Around ~5.6MB heap, so ~1.3MB regained.

[philmoz]

Warning for testing on H7 based radios from RadioMaster or Jumper - if your radio has firmware built prior to PR #6629 (commit 6235f01) then bootloader UF2 flashing will not work with this PR. The firmware image is 3.1MB; but the older bootloader only accepts UF2 images up to 2MB.

You can either update the radio to a newer version with the flash size fix first, or use the DFU flashing in Companion to install this PR.