Add benchmarks

[mattcieslak]

Adds documentation about the benchmarks and will add plots (once the benchmarks finish running)

[codecov]

Codecov Report

❌ Patch coverage is 88.02817% with 170 lines in your changes missing coverage. Please review.
✅ Project coverage is 85.25%. Comparing base (387ab5c) to head (bdd6632).
⚠️ Report is 25 commits behind head on main.

Files with missing lines	Patch %	Lines
src/trx.cpp	78.41%	101 Missing ⚠️
include/trx/trx.tpp	82.87%	68 Missing ⚠️
tests/test_trx_anytrxfile.cpp	99.75%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #28      +/-   ##
==========================================
+ Coverage   84.03%   85.25%   +1.21%     
==========================================
  Files          13       13              
  Lines        4724     6076    +1352     
  Branches      726      946     +220     
==========================================
+ Hits         3970     5180    +1210     
- Misses        754      896     +142     

Flag	Coverage Δ
linux	85.10% <87.22%> (+0.99%)	⬆️
macos	85.16% <88.00%> (+1.23%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.