Remove filter clear button from work packages view

User Story # 10350

Signed-off-by: Alex Coles <alex@alexbcoles.com>
Remove now obselete filter-clear directive

Signed-off-by: Alex Coles <alex@alexbcoles.com>
Test available responsibles endpoint for API v3
Add available assignees endpoint for API v3
Move spec to more appropriate folder
Add status filters to work package links.
Add API v3 support files
Move API v3 specs to appropriate directory
Merge pull request #1825 from opf/feature/10350-remove-clear-button
Merge pull request #1660 from opf/feature/14342_available_responsibles

14342 available responsibles
Merge pull request #1832 from opf/fix/links-to-work-packages-with-status

Add status filters to work package links.