Add a filter box to the applications page

[wlach]

This issue is intended as an onboarding task for potential outreachy applicants. Please do not work on it unless you have completed the initial qualification task and it has been assigned to you.

If you look at the bigquery table view, you'll see that there's a filter box that lets you easily search for the subset of columns that you're interested in:

We should have a similar widget on the main page to filter through the list of applications where e.g. putting "firefox" into the box will only show applications with Firefox in the name.

[wlach]

Assigning this to @DawoodShahat