This commit implements the basics of a new QueryPlanner implementation.

This commit implements the beginnings of a new query implementation by
generating an AST from the nested condition objects.

This commit applies bugfixes to the view and query implementation,
adding missing logic and imports.

This commit updates WisskiQueryDelegator::populateAdapterQueries to pass
constructor arguments to delegated $adapter->getQueryObject() calls.

For historical reasons, the implementation made several assumptions
about the query structure being flat. Instead of attempting to implement
support for the nested queries added in recent versions of Drupal, this
commit instead rewrites the query implementation based on the current
SQL Query implementation.

These changes were implemented jointly with several others during the
WissKI Hackathon in late 2020 and subsequent WissKI HackDays.
Thanks to everyone who participated, but in particular:

Arne Fitschen <fitschen@ub.uni-heidelberg.de>
Myriel Fichtner <myriel.fichtner@uni-bayreuth.de>
Mark Fichtner <m.fichtner@wiss-ki.eu>

Added first push towards translation - DO NOT USE YET, THIS WILL CORRUPT YOUR SYSTEM - DONT TOUCH - DANGER ZONE - NUKLEAR LAUNCH DETECED -

This commit adds a new method 'isFederatableSparqlQuery' to
'\Drupal\wisski_salz\WisskiQueryBase' to allow queries to declare if
they are federatable or not.

This was previously done by hard-coding specific class names in
'wisski_salz/src/Query/WisskiQueryDelegator.php' and
'wisski_salz/src/Query/WisskiQueryBase.php'. This commit updates the
previously hard-coded classes to make appropriate declarations.

This commit moves the Sparql11TriplesTabController from the
'wisski_adapter_sparql11_pb' module to the generic 'wisski_salz' module.
This is because it not longer implies any adapter-specific
functionality.

To avoid hard-coding names of engines into WisskiOntologyForm, this
commit adds a new method 'supportsOntology' to the
'Drupal\wisski_salz\EngineBase' class. This method allows engines to
declare if they support loading ontologies and by default returns false.

This commit also marks wisski_adapter_federated_sparql11_pb and
wisski_adapter_sparql11_pb engines as supporting the loading of
ontologies. This corresponds to the legacy behavior.

With the new version of EasyRDF several functions changed their names
and caused problems. This was partially caused by the query function
returing a Graph instead of a Result.

This commit fixes the bug by ensuring that a Result is always returned.

When setting an HTTP Authentication Header for a triple store
Sparql11Engine used a TextField. The default maximum length for a
TextField is 128. This turned out to cause a problem when the username
or password grows to long.

This commit increases the maximum length for the HTTP Authentication
Header Setting to 9999.

Previously, when no default local store was set an error message linking
to the route 'entity.wisski_salz_adapter.collection' was generated.
However this route no longer exists, causing an error.

This commit fixes the issue by linking to the
'entity.wisski_salz_adapter.canonical' route instead.

This commit adds a new 'query' operation to the sparql adapter
AdapterListBuilder. It links to the querying interface of each endpoint.

This commit adds a more detailed description on how to generate basic
authentication credentials on the command line for use with a WissKI
Salz adapter.

This commit updates the title and description for the WissKI Salz
Authentication Header.

This commit updates WissKI_Sparql_Client to make use of
`call_user_func_array` instead of directly passing an array to
$client->setHeaders.