Improve the handling with the pre set filter values.
Add a check if we have a valid metamodels.
Add support for filter.
Cleanup code.
Add the right function call for adding a filter rule to a filter.
Correct a misspelled path in the autoload.php
Change the sanitizeValue function based on the tags.
Merge branch 'contao3'

Conflicts:
	src/system/modules/metamodelsattribute_linkedselect/MetaModels/Attribute/Select/LinkedSelect.php
	src/system/modules/metamodelsattribute_linkedselect/MetaModels/Filter/Rules/FilterRuleLinkedSelect.php
	src/system/modules/metamodelsattribute_linkedselect/config/autoload.php