Removes "virtualdbtools" and its implementation under "simpledbt", which are
mostly wrappers around various dbtools functions and classes, previously aiding
the now removed dynamic loading logic.

Removes IDataAccessTools, IDataAccessTypeConversion and IDataAccessToolsFactory
interfaces and their accompanying implementations which are completely unused.

Removes IDataAccessCharSet (implemented by ODataAccessCharSet) and moves the
implementation into a function which replaces ODataAccessCharsetHelper.

Removes ISQLParseNode and ISQLParser and their implementation in
OSimpleParseNode and OSimpleSQLParser, which simply wrap around OSQLParseNode
and OSQLParser respectively. To avoid including "sqlbison.hxx" unnecessarily,
includes to "sqlbison.hxx" are now only used where needed.

Change-Id: Id882dfbf43514d84a1eaffc1f916d627830c8cd6
Reviewed-on: https://gerrit.libreoffice.org/15450Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: David Tardon <dtardon@redhat.com>