[pgAdmin4][Patch#2896] Add support for Tab/Shift Tab navigation in Query tool

Hi,

PFA patch to add keyboard navigation in Query tool module via
Tab/Shift-Tab key.
RM#2896

Please review.

*Note:*
1) Once the keyboard shortcut infrastructure is ready we will add generic
shortcut to focus out from CodeMirror editor and set foucs to next element,
Right now there is no way of doing this, For testing purpose you can
manually focus out from CodeMirror and click on data output panel to
continue navigate using Tab key.
2) As of now inner panel's are not getting focused on Tab/Shift-Tab keys
but once RM#2895 <https://redmine.postgresql.org/issues/2895> patch gets
committed it will start working automatically as it's inherited code which
will add tabindex tag automatically on each newly created wcDocker panel.

--
Regards,
Murtuza Zabuawala
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company