Introduce SectorVector

[mtfishman]

Introduce SectorVector as the analogy of SectorUnitRange for sector information attached to a vector. This is helpful when doing non-contiguous slices of SectorUnitRange and GradedUnitRange while preserving sector information.

[codecov]

Codecov Report

Attention: Patch coverage is 80.76923% with 5 lines in your changes missing coverage. Please review.

Project coverage is 94.03%. Comparing base (3b7447b) to head (ed3e495).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
src/sectorunitrange.jl	80.76%	5 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #48      +/-   ##
==========================================
- Coverage   94.49%   94.03%   -0.47%     
==========================================
  Files          20       20              
  Lines         799      821      +22     
==========================================
+ Hits          755      772      +17     
- Misses         44       49       +5     

Flag	Coverage Δ
docs	0.00% <0.00%> (ø)

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.