[editor] Create parser on par with existing autocompleter

The current SQL autocomplete in Hue has arbitrary support for various parts of a SQL statement and is built using regular expressions. In the current state it's difficult to maintain and improve.

The proper way is to use the grammar definition and generate a parser that supports autocomplete. We need something that reads similar to the grammar for each dialect so we know exactly where to implement changes or new features. For example the "Select Syntax" on: https://cwiki.apache.org/confluence/display/Hive/LanguageManual+Select

By doing this it will also allow us to suggest the right keyword based on the cursor position, currently it will suggest all possible keywords no matter where the cursor is.