[ADQL] Remove useless Javadoc (no custom javadoc for files automatically generated from the JavaCC grammar)

[TAP] Remake TAPFactory into an abstract class + let limit the number of jobs (async and sync) by allowing the TAPFactory to communicate with a connection pool

[TAP] Remove all generic types + Delete specific (for ResultSet) output formatters + Modify the main output formatter

1/ let the function ROUND having 2 parameters
2/ wrap Operations (WrappedOperand) with brackets when there are brackets in the ADQL query

ADQL: Fix an ADQL bug (raised by Dave Morris) in the management of subqueries: before, it was impossible to use (in a clause different from the FROM) columns of a father query inside a subquery.