Add more into-JSON coverage conversions

[ranweiler]

Add additional coverage conversions from in-memory structures directly into JSON-serializable formats. Note that we can now convert directly from coverage data into the JSON container enum (via conversion into the latest versioned format).

[codecov-commenter]

Codecov Report

Merging #2725 (f1123aa) into main (df40c99) will decrease coverage by 0.02%.
The diff coverage is 6.25%.

@@            Coverage Diff             @@
##             main    #2725      +/-   ##
==========================================
- Coverage   28.75%   28.72%   -0.03%     
==========================================
  Files         320      320              
  Lines       38191    38221      +30     
==========================================
  Hits        10980    10980              
- Misses      27211    27241      +30     

Impacted Files	Coverage Δ
...c/agent/onefuzz-file-format/src/coverage/binary.rs	66.66% <0.00%> (-33.34%)	⬇️
...c/agent/onefuzz-file-format/src/coverage/source.rs	66.66% <0.00%> (-33.34%)	⬇️
...gent/onefuzz-file-format/src/coverage/source/v1.rs	53.65% <14.28%> (-22.21%)	⬇️

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