Add APIs to support per keyboard glyph maps

DD: go/pk_glyph_map
PRD doc: go/pk_glyph_map_prd
This CL only contains the shell of the APIs, the implementation
will follow in subsequent CLs.

Test: None
Bug: 345440920
Flag: com.android.hardware.input.keyboard_glyph_map
Change-Id: I09e32121b8ed97dd5267b06d1ad86bb242bba880