add reframe api server

[petar]

Add a Reframe API HTTP server to STI.

Added end-to-end test with a Reframe Client calling FindProviders on the STI HTTP server's Reframe endpoint.

Change is safe to revert.

[codecov-commenter]

Codecov Report

Merging #464 (cff5416) into main (3a9bc5b) will increase coverage by 0.17%.
The diff coverage is 60.27%.

@@            Coverage Diff             @@
##             main     #464      +/-   ##
==========================================
+ Coverage   45.08%   45.26%   +0.17%     
==========================================
  Files          83       84       +1     
  Lines        6334     6407      +73     
==========================================
+ Hits         2856     2900      +44     
- Misses       3079     3099      +20     
- Partials      399      408       +9     

Impacted Files	Coverage Δ
server/finder/test/test.go	51.47% <55.00%> (+0.71%)	⬆️
server/reframe/reframe.go	63.33% <63.33%> (ø)
server/finder/http/server.go	88.88% <100.00%> (+0.65%)	⬆️

[petar]

@gammazero @willscott Ping to take a look at my responses.

[gammazero]

LGTM