Allow parsing unqualified DIDs

[mirgee]

Enables parsing of unqualified DIDs in did_parser, a temporary measure for the purposes of gracefully transitioning to using fully qualified DIDs, and will be reverted once the transition is complete.

[codecov-commenter]

Codecov Report

Merging #936 (3f3988d) into main (773113c) will increase coverage by 0.09%.
Report is 1 commits behind head on main.
The diff coverage is n/a.

❗ Current head 3f3988d differs from pull request most recent head 750bf18. Consider uploading reports for the commit 750bf18 to get more accurate results

@@            Coverage Diff             @@
##             main     #936      +/-   ##
==========================================
+ Coverage   44.16%   44.25%   +0.09%     
==========================================
  Files         418      418              
  Lines       29253    29311      +58     
  Branches     6234     6262      +28     
==========================================
+ Hits        12920    12973      +53     
+ Misses      12523    12512      -11     
- Partials     3810     3826      +16     

Flag	Coverage Δ
unittests-aries-vcx	44.25% <ø> (+0.09%)	⬆️

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

Files Changed	Coverage Δ
did_parser/src/did.rs	0.00% <ø> (ø)

... and 18 files with indirect coverage changes

[Patrik-Stas]

looks good but left some comments - consider them, otherwise feel free to merge