feat(rpc): Add top events support

[wmak]

• This allows the usage of top_events with the useRpc param
• TODO: going to add proper SearchResolver column caching, its being called quite heavily by these changes
• TODO: going to follow up with more rigorous testing

[codecov]

Codecov Report

Attention: Patch coverage is 94.11765% with 5 lines in your changes missing coverage. Please review.

✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
src/sentry/search/eap/spans.py	77.77%	4 Missing ⚠️
src/sentry/snuba/spans_rpc.py	98.46%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           master   #81217       +/-   ##
===========================================
+ Coverage   58.28%   80.34%   +22.06%     
===========================================
  Files        7203     7215       +12     
  Lines      318916   319529      +613     
  Branches    20776    20776               
===========================================
+ Hits       185885   256732    +70847     
+ Misses     132637    62403    -70234     
  Partials      394      394