lib: Split-off regular grammar parser

in preparation for ANTLR-based valiadators, #9
2 jobs for master in 19 seconds (queued for 12 seconds)
Name Stage Failure
failed
unittest Test
E   ModuleNotFoundError: No module named 'lib.parser.RegGLexer'
=========================== short test summary info ============================
ERROR test_cfl_cfg.py
ERROR test_reg.py
!!!!!!!!!!!!!!!!!!! Interrupted: 2 errors during collection !!!!!!!!!!!!!!!!!!!!
============================== 2 errors in 0.43s ===============================
make: *** [Makefile:13: unit] Error 2
Cleaning up file based variables
ERROR: Job failed: exit code 1