Find repository with substrings (BB-9687)

Currently, the Find Repository search box must match the start of the repository name. It would be very helpful to have any substring found in the name, or use wildcards at the start (I'm fine with full regex requiring .* as well).

For example, if a repo is names products_apollo-server, I should be able to search for just apollo and find it (or apollo).

If searching the entire bitbucket site is too heavy in this way, it would still be beneficial to at least do this type of search within the current teams.

(Our team is using repository names prefixes in lieu of repository organization, like products_, libjava_, tools_, etc. Eventually, we hope to have folders or something like that, as requested elsewhere BB-1086.