Extract message sending from prover & verifier SMs

[mirgee]

Extracts message sending out of prover and verifier state machines and handlers. Transition functions are now returning messages constructed to be sent and are not accepting message-sending closures.

Prover

Handlers

• send_proposal -> build_presentation_proposal
• send_presentation -> mark_presentation_sent
• Removed set_presentation

State machine

• send_presentation_proposal -> build_presentation_proposal
• send_presentation -> mark_presentation_sent (now throws in invalid state)
• Added get_problem_report, get_presentation_proposal
• Removed set_presentation

Verifier

Handlers

• send_presentation_request -> mark_presentation_request_sent (now throws in invalid state, TODO: better name)
• set_request -> set_presentation_request
• Removed mark_presentation_request_msg_sent, get_presentation_request

State machine

• set_request -> set_presentation_request
• mark_presentation_request_msg_sent -> mark_presentation_request_sent
• Added get_final_message

verify_presentation now generates and stores either presentation or problem report, which can then be retrieved via get_final_message.

[codecov-commenter]

Codecov Report

Merging #965 (b33f23d) into main (313db9f) will decrease coverage by 0.03%.
Report is 2 commits behind head on main.
The diff coverage is 45.67%.

@@            Coverage Diff             @@
##             main     #965      +/-   ##
==========================================
- Coverage   39.25%   39.23%   -0.03%     
==========================================
  Files         417      415       -2     
  Lines       28959    28867      -92     
  Branches     6186     6173      -13     
==========================================
- Hits        11368    11325      -43     
+ Misses      14250    14202      -48     
+ Partials     3341     3340       -1     

Flag	Coverage Δ
unittests-aries-vcx	39.23% <45.67%> (-0.03%)	⬇️

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

Files Changed	Coverage Δ
aries_vcx/tests/utils/devsetup_util.rs	52.70% <0.00%> (-1.04%)	⬇️
...otocols/proof_presentation/prover/state_machine.rs	45.68% <20.83%> (+2.88%)	⬆️
...es_vcx/src/handlers/proof_presentation/verifier.rs	44.44% <24.44%> (-6.30%)	⬇️
...ries_vcx/src/handlers/proof_presentation/prover.rs	44.26% <28.57%> (+0.35%)	⬆️
...ocols/proof_presentation/verifier/state_machine.rs	52.32% <34.48%> (-3.63%)	⬇️
aries_vcx/tests/utils/scenarios.rs	82.83% <89.65%> (-0.28%)	⬇️
...tation/prover/states/presentation_proposal_sent.rs	38.46% <100.00%> (ø)
aries_vcx/tests/test_creds_proofs.rs	88.39% <100.00%> (+0.07%)	⬆️
aries_vcx/tests/utils/devsetup_alice.rs	72.34% <100.00%> (ø)
aries_vcx/tests/utils/devsetup_faber.rs	80.50% <100.00%> (ø)

... and 17 files with indirect coverage changes

[Patrik-Stas]

Left some comments, consider them, but generally lgtm.

In line with Connection protocol, Didexchange protocol, changes done in Issuer/Verifier I'd suggest to get rid of marker states, but that's again something that can be discussed and addressed outside of this PR.