Implement oem type

[matzipan]

Closes #117

• Add support for state vector parsing
• Implement parser for state vector
• Implement parser for covariance matrix
• Add tests
• Add rustdoc
• Fix bug for missing segment
• Add support for META_START/STOP
• Implement construction for OemCovarianceMatrixType
• Add support for COVARIANCE_START/STOP

[codecov]

Codecov Report

Attention: Patch coverage is 98.23213% with 23 lines in your changes missing coverage. Please review.

Project coverage is 88.44%. Comparing base (4d9acef) to head (46235dd).
Report is 8 commits behind head on main.

Files	Patch %	Lines
crates/lox-io/src/ndm/kvn/parser.rs	95.51%	16 Missing ⚠️
crates/lox-io/src/ndm/oem.rs	99.35%	6 Missing ⚠️
crates/lox-io/src/ndm/common.rs	75.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #130      +/-   ##
==========================================
+ Coverage   84.92%   88.44%   +3.51%     
==========================================
  Files          84       84              
  Lines       37964    50981   +13017     
==========================================
+ Hits        32241    45090   +12849     
- Misses       5723     5891     +168     

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[helgee]

Please prefix your branch names with your initials, e.g. az/implement_oem_type.