Expose multiple connection-related methods

[mirgee]

• Expose Ping, PingResponse and HandshakeReuseAccepted message builder
• Expose credential and credential offer sending via nonmediated connection
• Expose issuer and proof state updating via nonmediated connection
• Expose existing nonmediated connection checking for out of band
• Expose problem report processing for nonmediated connection

[codecov-commenter]

Codecov Report

Merging #741 (6449e67) into main (66ee076) will decrease coverage by 0.03%.
The diff coverage is 29.41%.

@@            Coverage Diff             @@
##             main     #741      +/-   ##
==========================================
- Coverage   54.73%   54.70%   -0.03%     
==========================================
  Files         363      363              
  Lines       37122    37144      +22     
  Branches     8089     8098       +9     
==========================================
+ Hits        20317    20321       +4     
- Misses      10832    10855      +23     
+ Partials     5973     5968       -5     

Flag	Coverage Δ
unittests-aries-vcx	54.60% <29.41%> (-0.03%)	⬇️

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

Impacted Files	Coverage Δ
aries_vcx/src/handlers/connection/connection.rs	56.01% <0.00%> (-2.16%)	⬇️
aries_vcx/src/protocols/trustping/mod.rs	75.00% <0.00%> (-10.72%)	⬇️
aries_vcx/src/handlers/out_of_band/receiver.rs	37.96% <58.33%> (-1.09%)	⬇️
...vcx/src/handlers/connection/mediated_connection.rs	63.29% <100.00%> (+0.22%)	⬆️
.../src/protocols/connection/invitee/state_machine.rs	66.54% <100.00%> (+0.18%)	⬆️
libvdrtools/src/services/pool/pool.rs	48.05% <0.00%> (-0.19%)	⬇️
libvdrtools/src/services/pool/networker.rs	75.51% <0.00%> (+0.40%)	⬆️
libvdrtools/src/controllers/non_secrets.rs	47.80% <0.00%> (+0.48%)	⬆️

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[Patrik-Stas]

Can we close in favor of #739 ?