Add a search_type filter for exact, contains and startsWith search modes

[cen1]

The current name param returns package by exact match however, I needed a more extended functionality on my FE to search by partial match and a "starts with" for an Alphabet filter.

I could have just changed how the name filter works (make the value a LIKE syntax value for example) but that would break backward compat. Second option was to add a new search param like name_starts_with, but then I decided on a third option to switch between modes and have exact be the default.

Could possibly need to have to name this name_search_type if you'd want to do something similar with another field (version?) but not seeing a use case rn.

Client side:

curl "http://localhost:8484/api/v1/packages/binary?name=nano&search_type=exact" |jq
curl "http://localhost:8484/api/v1/packages/binary?name=ano&search_type=contains" |jq
curl "http://localhost:8484/api/v1/packages/binary?name=nan&search_type=starts_with" |jq

[cen1]

Added some integration tests, I think it should be g2g.