Don't use build and release directories

[tanadeau]

The SDK delivers several archive (.a files). For example:

• platform/emdrv/nvm3/lib/libnvm3_CM33_gcc.a
• platform/radio/rail_lib/autogen/librail_release/librail_efr32xg22_gcc_release.a
• protocol/bluetooth/bgcommon/lib/build/gcc/cortex-m33/bgcommon/release/libbgcommon.a
• protocol/bluetooth/bgstack/ll/lib/libbluetooth_controller_efr32xg22_gcc_release.a
• protocol/bluetooth/build/gcc/cortex-m33/bt_host/hal/release/libbt_hal_series2.a
• protocol/bluetooth/build/gcc/cortex-m33/bt_host/release/libbt_host.a

Common .gitignore and similar configurations will ignore build, debug, release, etc. directories from version control. If using the SDK copy strategy for vendoring purposes, the needed .a files will be ignored. Similar to the emdrv or rail_lib examples above, can the bluetooth stack's .a files be put into a lib or lib_release directory? The current workaround would be to git add -f the files; however, forgetting the workaround results in very strange compilation errors.