[FE] Add "Filter results" control on Group Value Stream Analytics

FE for #12525 (comment 342589632)

In group-level Value Stream Analytics:

• add a "Filter results" input to the control panel/div, between the project selector and the date range selector (like what exists for Productivity Analytics (see example
• filter input remains disabled until a project has been selected from the dropdown - this was removed
• enable these filter options with = capability (no != capability, that's out of scope):
  • assignee
  • author
  • label
  • milestone
• filter options should apply to all all issue and merge request queries that the feature executes
• filter options are deep linked (like existing filters)