shader/track: Add a more permissive global memory tracking

Port citra-emu/citra#4603: "gdbstub: only let Execute breakpoints write/restore BKPT opcodes into target memory"

gl_shader_cache: Disk based shader cache

Co-Authored-By: ReinUsesLisp <reinuseslisp@airmail.cc>

Co-Authored-By: ReinUsesLisp <reinuseslisp@airmail.cc>

Co-Authored-By: ReinUsesLisp <reinuseslisp@airmail.cc>

Co-Authored-By: ReinUsesLisp <reinuseslisp@airmail.cc>

i965 (and probably all mesa drivers) require GL_PROGRAM_SEPARABLE when using
glProgramBinary. This is probably required by the standard but it's ignored by
permisive proprietary drivers.

maxwell_3d: Allow texture handles with TIC id zero

gl_rasterizer: Use DSA for textures and move swizzling to texture state

Port citra-emu/citra#4586: "Use QPixmap/QIcon for background color selection button"

Port citra-emu/citra#4583: "citra_qt: Fix saving screenshot when no file extension is provided"