Create AskarWallet in AFJ

[TimoGlastra]

Description

In order to move towards the complete removal of the dependency on indy-sdk, we need to replace its storage/wallet related functionality by leveraging the aries-askar Rust package. This functionality will be handled by a new and separate package called @aries-framwork/aries-askar. This package will interface with the aries-askar's JavaScript wrapper and match the Wallet interface.

Todo

• Create a new package called @aries-framwork/aries-askar.
  • Alternatively, you can copy and modify one of the existing packages, this saves you some TypeScript, ESLint and Jest configuration.
• Add the JavaScript wrapper dependency and verify that everything works as expected.
• Create a class called AskarWallet that implements the Wallet interface and implement all methods.
• Write tests