feat(anoncreds): auto create link secret

[genaris]

As discussed in July 6th WG call, here we add an optional configuration parameter for anoncreds-rs and indy-sdk modules that makes holder services to auto create a default link secret if no one has been created yet. This check is performed only when it is actually needed (i.e. when creating a credential request) rather than at agent initialization.

It defaults to true, meaning that normally it will not be needed to the consumer to do any specific logic to use AnonCreds as a holder.

Superseeds #1491 and fixes #1490

[codecov-commenter]

Codecov Report

Merging #1521 (98b8913) into main (08cdf1b) will increase coverage by 23.61%.
The diff coverage is 56.41%.

@@             Coverage Diff             @@
##             main    #1521       +/-   ##
===========================================
+ Coverage   62.14%   85.76%   +23.61%     
===========================================
  Files         773      945      +172     
  Lines       17955    22637     +4682     
  Branches     3046     3924      +878     
===========================================
+ Hits        11159    19414     +8255     
+ Misses       6261     3040     -3221     
+ Partials      535      183      -352     

Impacted Files	Coverage Δ
...ckages/anoncreds-rs/src/AnonCredsRsModuleConfig.ts	14.28% <0.00%> (ø)
packages/anoncreds/tests/legacyAnonCredsSetup.ts	75.75% <ø> (ø)
packages/indy-sdk/src/IndySdkModuleConfig.ts	77.77% <0.00%> (ø)
tests/e2e-test.ts	100.00% <ø> (ø)
...sdk/src/anoncreds/services/IndySdkHolderService.ts	8.02% <14.28%> (ø)
...ncreds-rs/src/services/AnonCredsRsHolderService.ts	87.64% <28.57%> (+1.58%)	⬆️
packages/anoncreds/src/utils/linkSecret.ts	85.71% <85.71%> (ø)
packages/anoncreds/src/AnonCredsApi.ts	71.27% <100.00%> (+53.97%)	⬆️
packages/anoncreds/src/index.ts	100.00% <100.00%> (ø)
packages/anoncreds/src/utils/index.ts	100.00% <100.00%> (ø)

... and 464 files with indirect coverage changes

[TimoGlastra]

Great! :)