Split integration tests

[Patrik-Stas]

Currently, aries_vcx/tests essentially contain 2 classes of tests:

1. Protocol tests which aim to test implementation of protocols and various state they may enter. Ultimately these (and surrounding testing infrastructure / testing workflows) are also testing and demonstrating the public API of aries_vcx crate
2. Anoncreds/ledger/wallet related tests. These tend to use the aries_vcx public API as well, but only because it's convenient, as we already have the workflows needed to perform various setups. For example:
   • revocation: We have tests where we issue multiple credentials, revoke some, then verify some of them
   • rev reg rotation: we have tests where we issue creds across multiple revocation registries
   • wallet: we have tests where we issue prover some credentials (via full blown aries protocols, only because it's convenient atm) only to test capabilities of prover to retrieve the credential data from wallet, given various proof requests.
   • ledger tests - writing DIDs on ledger, writing anoncreds primitives on ledger, public DID rotation etc.

While the category 1. correctly represent what aries_vcx integration tests should be like, the second category is currently misplaced and should be pulled down to aries_vcx_core (or rather the individual components which aries_vcx_core will be soon broken down into)