refactor: Use typed-builder instead of custom one for VerificationMethod

[Patrik-Stas]

• VerificationMethod construction was designed to be done via custom builder. With little to no benefit this become even more cumbersome with introduction of DidPeer4VerificationMethod as we would have to decide to either copy the approach or settle for inconsistency in construction approach.
• Removal of the the custom builder also enable deletion of number of tests, which were particularly aimed to test builder logic.

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 0% with 42 lines in your changes are missing coverage. Please review.

Project coverage is 0.05%. Comparing base (05c92f2) to head (729eb9a).

Files	Patch %	Lines
.../peer_did/numalgos/numalgo2/verification_method.rs	0.00%	21 Missing ⚠️
...src/peer_did/numalgos/numalgo4/encoded_document.rs	0.00%	9 Missing ⚠️
...d_methods/did_resolver_sov/src/resolution/utils.rs	0.00%	6 Missing ⚠️
...rc/protocols/did_exchange/state_machine/helpers.rs	0.00%	5 Missing ⚠️
...core/did_doc/src/schema/verification_method/mod.rs	0.00%	1 Missing ⚠️

Additional details and impacted files

@@          Coverage Diff           @@
##            main   #1162    +/-   ##
======================================
  Coverage   0.05%   0.05%            
======================================
  Files        485     484     -1     
  Lines      24332   24165   -167     
  Branches    4511    4489    -22     
======================================
  Hits          13      13            
+ Misses     24319   24152   -167     

Flag	Coverage Δ
unittests-aries-vcx	0.05% <0.00%> (+<0.01%)	⬆️

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