WebSearch: new Add-to-Search Interface

* New search box interface that contains both simple search and advanced
  search (javascript dependent).  (addresses #622)

* Replaces the 3-line advanced search, with only 1-line add-to-search,
  with the possibility of adding patterns to the current search pattern.

* Ammends regression tests to take into account a third search
  interface.

* Moves the config variables `CFG_WEBSEARCH_ENABLED_SEARCH_INTERFACES`
  and `CFG_WEBSEARCH_DEFAULT_SEARCH_INTERFACES` from the `inveniocfg.py`
  to `search_engine_config.py` and `invenio.config`
  respectively.  (closes #271)  (PR #1738)

Signed-off-by: Ludmila Marian <ludmila.marian@gmail.com>
Co-authored-by: Esteban J. G. Gabancho <esteban.gabancho@gmail.com>
Reviewed-by: Tibor Simko <tibor.simko@cern.ch>
webcoll: fix for "--language" option

* Fixes cache re-creation for a subset of all available
  languages.  (closes #1399) (PR #2219)

Reviewed-by: Tibor Simko <tibor.simko@cern.ch>
BibMerge: `onclickSubmitButton` missing comma fix

* Fixes missing comma in `onclickSubmitButton`.  (PR #2230)

Reviewed-by: Tibor Simko <tibor.simko@cern.ch>
WebSearch: fix for record numbering in pagination

* Adds optional `nb_found` argument to `print_records` allowing for a
  different list of records to be printed and number of records found,
  when we are only printing a subset of a total number of records
  found.  (closes #1762) (PR #1763)

Signed-off-by: Nikolaos Kasioumis <nikolaos.kasioumis@cern.ch>
Reviewed-by: Tibor Simko <tibor.simko@cern.ch>
WebSubmit: link to successfully created record

* Shows link to new record if possible.  (closes #1641)

Signed-off-by: Patrick Glauner <patrick.oliver.glauner@cern.ch>
Tested-by: Tibor Simko <tibor.simko@cern.ch>
BibRank: fix of similar-to-recid result order

* Fixes order of results.  (addresses #1745) (PR #2236)

Signed-off-by: Patrick Glauner <patrick.oliver.glauner@cern.ch>
Reviewed-by: Tibor Simko <tibor.simko@cern.ch>
SolrUtils: fix of similar-to-recid result order

* Fixes order of results.  (closes #1745) (PR #2236)

Signed-off-by: Patrick Glauner <patrick.oliver.glauner@cern.ch>
Reviewed-by: Tibor Simko <tibor.simko@cern.ch>