PromQL(subset) parser

It can only parse a very small subset of PromQL, and add a new label selector to every metric.

checkout 5 test cases in yacc_test.py:

python3 yacc_test.py

dependencies:

Name		Name	Last commit message	Last commit date
Latest commit History 1 Commit
ply		ply
.gitignore		.gitignore
README.md		README.md
lexer.py		lexer.py
lexer_test.py		lexer_test.py
promql_ast.py		promql_ast.py
yacc.py		yacc.py
yacc_test.py		yacc_test.py

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