Merge branch 'topic/stream_enhancements' into 'master'

Make StreamConcat work only on LKQLStream as lhs

Add Iterable.to_stream method

Simplify inner structure of BaseCachedStream

Add EmptyStream

Throw exceptions when accessing an empty stream

Add head and tail builtins to Stream

Fix cache sharing of LKQLConsStream

Merge branch 'topic/escape_instance_args' into 'master'

Make sure instance string args are escaped

Merge branch 'topic/ci/add_private_gnatcheck_test' into 'master'

Add an optional run of the GNATcheck internal testsuite in the CI

Add a run of the GNATcheck testsuite with the 'private' qualifier

Merge branch 'topic/lkql/remove_withed_project' into 'master'

Remove the 'withed_projects' file from the lkql spec