feat(eap-spans): add perf score function

[DominikB2014]

Closes https://github.com/getsentry/team-visibility/issues/37

1. Implements performance_score(x) function
2. Adds attribute_resolver to AggregateDefinition to handle more complicated aggregates where we don't simply aggregate on the parameter.
3. Some refactoring to improve readability and logic

[codecov]

Codecov Report

Attention: Patch coverage is 92.15686% with 4 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/resolver.py	86.66%	2 Missing ⚠️
...endpoints/test_organization_events_span_indexed.py	88.88%	2 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           master   #87127       +/-   ##
===========================================
+ Coverage   46.15%   87.76%   +41.61%     
===========================================
  Files        9841     9853       +12     
  Lines      556950   557727      +777     
  Branches    21989    21902       -87     
===========================================
+ Hits       257042   489490   +232448     
+ Misses     299524    67807   -231717     
- Partials      384      430       +46     

[DominikB2014]

Fyi, I moved the arguments validator under if index < len(arguments). Otherwise we could run into index out of range issues.

i.e we only need to validate arguments, if there's an argument that's being passed in