Introducing parser to directory search

[lisa-kwok]

Is your feature request related to a problem? Please describe.
Current directory search are written to query the db directly. With a parser implemented in between the user query and db, it can filter the search query and send the appropriate queries to the db. Such as stripping away go.gov.sg/ in the user query or directing user email query to the email column. This also allows universal search through a single search bar instead of toggling between different types of search.