common/peg : refactor until gbnf grammar generation (#24839)
* common/peg : refactor until gbnf grammar into an ac automaton
* cont : add a test with multiple strings
* cont : pad state with 0s so rules line up
* cont : clean up comments
* cont : use set everywhere
* cont : inline state num string padding
* cont : add a ref to PR
* cont : fix regression in server-tools.cpp
