Implement in-browser task search

[andy-opal]

This PR implements searching through tasks by keyword, regex or custom JS code. The search is executed in the browser.

Due to the nature of this PR, the implementation has some hacks, please let me know if you have suggestions for better approaches or improvement ideas.

Caveats

• Searching aggregating tasks is not supported yet
• As the search is performed in the browser, and since we are restricted to linear search, this approach does not scale very well. However:
  • I have tested it with 100K tasks with each task containing a ~500 char JSON object. The search completes in roughly 10s and JS heap usage increased by 70MB after the search. Therefore I expect this implementation will be fine for at least 1 mil tasks.

Demo video

Screen.Recording.2022-05-17.at.9.31.17.PM-fastflix-70d6_3.mp4