ENH: Add custom tsquery from websearch function and related tests

[adelavega]

Added custom function to parse websearches as in a "quasI" pubmed like format.

The custom parser does the following:

• Converts "AND" "OR" "NOT" to tsquery
• Respects parentheses, and treats groups of parentheses as units
• Quotes specifically mean that words in quote must be in specific order. Currently it does not mean that special chars are escaped (e.g. parantheses), although we could add that. It also potentially behaves strangely if dashes are in quotes (e.g. "pre-diagnosis").

Needs additional testing to ensure behavior is as expected. I added a few queries, but more would be helpful.
Could have undefined behavior if invalid combination of parens and quotes are used, but to be fair this is just an invalid queries.

Needed from API side:

• Confirmation from @jdkent that correct change to code was made
• Return error codes to user via API
• Test actual queries on db to ensure tsquery behaves as expected

@jdkent can you take this and run with it?

[adelavega]

Should we disallow special characters in quotes?
"Autism Spectrum Disorder (ASD)" --- add to test case

[adelavega]

"pre-diagnosis" - can we get a document that has this term in it.

currently: "pre-diagnosis" compiles to PRE<->DIAGNOSIS

should it be "PRE-DIAGNOSIS" instead?