refactor: A few refactoring of legacy-connection package

[Abdulbois]

Title:
Refactor legacy-connection package due to interoperability issues

Summary:

• Add new legacy http header to handle legacy requests. Cover with unit tests
• Encode invitation Recipient key to base58
• Change embedded verification to referenced while creating verification methods
• Add legacy file into doc package to convert DIDdoc to raw doc. Cover with unit test
• Add handling DID id's where did method is not specified
• Add JSONBytes and ParseConnection methods to use them while handling connection data
• Change AckMsgType content to proper one
• Add method to convert array of did-keys to base58 keys
• Enable saving decryption key while handling envelope at connection-request state
• Add new InvitationRecipientKeys into connection.Record model
• Refactor requestMsgRecord, handleInboundRequest and prepareConnectionSignature methods and their unit-tests
• Save Recipient keys while handling connection request
• Use SaveDID instead SaveDIDByResolving

[codecov]

Codecov Report

Merging #3342 (f2d219e) into main (77fbef7) will decrease coverage by 0.00%.
The diff coverage is 85.16%.

@@            Coverage Diff             @@
##             main    #3342      +/-   ##
==========================================
- Coverage   87.90%   87.89%   -0.01%     
==========================================
  Files         328      330       +2     
  Lines       45336    45498     +162     
==========================================
+ Hits        39854    39992     +138     
- Misses       4061     4079      +18     
- Partials     1421     1427       +6     

Impacted Files	Coverage Δ
pkg/didcomm/transport/http/outbound.go	81.94% <ø> (ø)
pkg/store/connection/connection_lookup.go	94.25% <ø> (ø)
...comm/dispatcher/inbound/inbound_message_handler.go	90.24% <36.36%> (-3.13%)	⬇️
pkg/didcomm/protocol/legacyconnection/models.go	72.09% <72.09%> (ø)
pkg/didcomm/protocol/legacyconnection/states.go	87.16% <80.00%> (-0.30%)	⬇️
pkg/doc/did/doc.go	86.98% <83.33%> (+0.36%)	⬆️
pkg/doc/did/legacy.go	92.77% <92.77%> (ø)
pkg/didcomm/protocol/legacyconnection/keys.go	88.46% <100.00%> (-0.22%)	⬇️
pkg/didcomm/protocol/legacyconnection/service.go	86.81% <100.00%> (+0.22%)	⬆️
pkg/didcomm/transport/http/inbound.go	81.44% <100.00%> (ø)
... and 3 more

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[ashcherbakov]

Are we planning to write an integration acceptance test in af-go that will check the interoperability between af-go legacy connection protocol and other implementations (VCX in particular)? Will a BDD test do these checks? Or we need another one?