Use concordium-base wallet library

[orhoj]

Purpose

Use wallet_library from concordium-base to create identity requests, identity recover requests and for creating unsigned credentials.

This also comes with the addition of two new methods for creating these:

• Creating an identity request without providing the whole seed,
• Creating an identity recovery request without providing the whole seed.

Changes

• Remove custom implementations from rust-bindings and depend on wallet_library in concordium-base instead.
• Expose three new WASM entrypoints (createIdRequestWithKeysV1, createIdentityRecoveryRequestWithKeys and createUnsignedCredentialWithKeysV1) from rust-bindings. Updated SDK accordingly to provide access to this functionality.
• Change WASM entrypoint createUnsignedCredentialV1 to use the seed instead of being the function that takes the secret key material directly.
• Update example/wallet to use identity creation and unsigned credential creation that does not provide the whole seed to the library.

Checklist

• My code follows the style of this project.
• The code compiles without warnings.
• I have performed a self-review of the changes.
• I have documented my code, in particular the intent of the
  hard-to-understand areas.
• (If necessary) I have updated the CHANGELOG. I accept the above linked CLA.

[soerenbf]

Looks good with a nice chunk of code removed 🥇

As mentioned in one of the comments, it would be good if we could add documentation in the form of jsdoc to at least everything new we export 😄