Separate out "GN builder" for the unified build script

[andy31415]

Problem

gn gen and ninja -C are very commonly used for our global builds. Some embedded platforms use their own tooling (e.g. idf.py or west) however for other cases and notably host builds, gn is standard.

This builds on #8295

Change overview

Centralize GnBuilder as a reusable class for the build system. This will make it easier to perform any global changes requied when running gn (e.g. using 'check' and similar

Testing

Unit tests pass. Ran manual build of --platform all and it passed

[github-actions]

Size increase report for "esp32-example-build" from cbf106e

File	Section	File	VM
chip-all-clusters-app.elf	.flash.text	-16	-16
chip-temperature-measurement-app.elf	.flash.text	-60	-60

Full report output

BLOAT REPORT

Files found only in the build output:
    report.csv

Comparing ./master_artifact/chip-pigweed-app.elf and ./pull_artifact/chip-pigweed-app.elf:

sections,vmsize,filesize

Comparing ./master_artifact/chip-persistent-storage.elf and ./pull_artifact/chip-persistent-storage.elf:

sections,vmsize,filesize

Comparing ./master_artifact/chip-shell.elf and ./pull_artifact/chip-shell.elf:

sections,vmsize,filesize

Comparing ./master_artifact/chip-all-clusters-app.elf and ./pull_artifact/chip-all-clusters-app.elf:

sections,vmsize,filesize
.xt.prop._ZN4chip6System5Mutex6UnlockEv,0,108
.xt.lit._ZN4chip11DeviceLayer8Internal35GenericPlatformManagerImpl_FreeRTOSINS0_19PlatformManagerImplEE14_LockChipStackEv,0,48
.xt.lit._ZN4chip11DeviceLayer8Internal35GenericPlatformManagerImpl_FreeRTOSINS0_19PlatformManagerImplEE15_StartChipTimerEj,0,48
.xt.lit._ZN4chip11DeviceLayer8Internal35GenericPlatformManagerImpl_FreeRTOSINS0_19PlatformManagerImplEE16_UnlockChipStackEv,0,48
[Unmapped],0,16
.xt.prop._ZN4chip11DeviceLayer8Internal35GenericPlatformManagerImpl_FreeRTOSINS0_19PlatformManagerImplEE14_LockChipStackEv,0,12
.xt.prop._ZN4chip11DeviceLayer8Internal35GenericPlatformManagerImpl_FreeRTOSINS0_19PlatformManagerImplEE15_StartChipTimerEj,0,12
.xt.prop._ZN4chip11DeviceLayer8Internal35GenericPlatformManagerImpl_FreeRTOSINS0_19PlatformManagerImplEE16_UnlockChipStackEv,0,12
.flash.text,-16,-16
.xt.prop._ZN4chip11DeviceLayer8Internal26GenericPlatformManagerImplINS0_19PlatformManagerImplEE14_InitChipStackEv,0,-40
.xt.lit._ZN4chip11DeviceLayer8Internal35GenericPlatformManagerImpl_FreeRTOSINS0_19PlatformManagerImplEE10_PostEventEPKNS0_15ChipDeviceEventE,0,-80
.xt.lit._ZN4chip6System5Mutex6UnlockEv,0,-128

Comparing ./master_artifact/chip-lock-app.elf and ./pull_artifact/chip-lock-app.elf:

sections,vmsize,filesize

Comparing ./master_artifact/chip-temperature-measurement-app.elf and ./pull_artifact/chip-temperature-measurement-app.elf:

sections,vmsize,filesize
[Unmapped],0,60
.flash.text,-60,-60