Extract subset of changes made in #928

[mirgee]

Extracts changes made to did_doc, did_doc_sov, did_doc_sov, did_peer, and public_key crates in #928. Most of these changes are either consequences of #913 or additions of features found to be useful during #928.

The reason for extracting these changes is that

• doing so will minimize conflicts encountered when rebasing DID Exchange Protocol #928 after changes made to the modified crates (e.g. in Attempt to convert legacy DID documents to new during deserialization #938),
• they are independent and useful outside of DID Exchange Protocol #928.

TODO: Prune

[codecov-commenter]

Codecov Report

Merging #939 (ef7de69) into main (3321031) will decrease coverage by 0.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##             main     #939      +/-   ##
==========================================
- Coverage   44.25%   44.25%   -0.01%     
==========================================
  Files         418      418              
  Lines       29311    29311              
  Branches     6262     6262              
==========================================
- Hits        12973    12972       -1     
- Misses      12512    12513       +1     
  Partials     3826     3826              

Flag	Coverage Δ
unittests-aries-vcx	44.25% <ø> (-0.01%)	⬇️

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

Files Changed	Coverage Δ
public_key/src/key.rs	0.00% <ø> (ø)

... and 1 file with indirect coverage changes