Improved Span Search

[davit-y]

This is a centralized issue for all the PRs related to improving span search on the trace page.

PRs

• Span Search - Add result count, navigation and clear buttons #234 Initial UI Improvements (navigation and clear buttons, result count, shortcuts)
• Span Search - Improve search logic #237 Search query improvements (search by tags, processes, log, and ignore keys)
• Span Search - Highlight search results #238 Improve result highlighting

[tiffon]

Ran across an interesting way of demarcating matches where the match is currently hidden due to collapsing.

[tiffon]

Closing, as the PRs called out (#234, #237, #238) are already merged.