Add hoa compiler
WIP on PP grammar
Add config watcher

requires `entr` binary
WIP query grammar
Sample PP grammar
New query parser between Hoa compiler and search engine
AST revamp
Updated grammar (IN/AND/EXCEPT)
Parse tree visitor to build ES query
New query debug command
Cleanup QueryParser & SearchQuery
Search\SearchQuery -> Search\Query
Refactor query visitor
Add compiler AST dump to debug command
Brackets support in queries
Add Except query support
Better query error handling
Proper left-associativity in query operators

Remove previous lambda/curring based method
Grammar was simplified for EXCEPT case
Cleanup unused constants
Query command option to disable AST postprocessing
Plug new parser on search engine