Search

**Is your feature request related to a problem? Please describe.**
Users should be able to search for promises or evidences. There is currently no way to search!

**Describe the solution you'd like**
Add a search bar to the tracker that searches on:
[P0] Promises
[P1] Evidences (a bit tricky as it's effectively a linking table, might need to just show every activity<>promise pair)

Search bar should probably live in the left hand column, as it should do a global search, not just search on the department/ministry being shown.

Start by locating the tracker’s left-column layout and the data paths for Promises and Evidences. Confirm how a global search can cover both, including the activity–promise pairs mentioned for Evidences; it is done when the search bar returns the requested results independently of the displayed department or ministry.

Written by the indexing model from the issue text.