Introduce account repository

[zaychenko-sergei]

1. AuthenticationRepository:

   • AccountID should be a DID string like DatasetID
   • Repository: associate account's ID and name, resolve ID by name or name by ID
   • Repository: control uniqueness of visible account IDs and names
   • Implementations:
     • Tests/CLI: in-memory
     • Node: store in database:
       • Postgres
       • MySQL
       • SQlite

2. AuthenticationService: find by AccountID operation:

   • look only in authentication repository!

3. CLI AccountService should use real AccountIDs:

   • automatic registration of known accounts at startup:
     • single-tenant: default must be registered
     • multi-tenant: all predefined must be registered
   • predefined config:
     • store ID: for demo, generate DID from name
     • register ID in Authentication repository
   • login unknown:
     • try auto-creating, if not exists, generate random DID
     • saving name -> id association in Authentication repository

4. OAuthGithub should interact to extract real AccountID:

   • resolve by email, if exists
   • auto-creating, if not exists, generate random DID

5. CurrentAccountSubject:

   • should hold real account ID for logged users - to use in various services, i.e. in flow triggers.

6. (REEVALUATE) Token store (kamu login) should store AccountID instead / in addition to name

7. GraphQL API adjustments:

   • Account.byId operation
   • Account.from_account_name
   • Account.from_dataset_alias
   • Datasets.byAccountId operation
   • Flows: InitiatorFilterInput should use AccountID

8. Remove hard-coded dummy IDs:

   • image build scripts in kamu-cli - set fixed DIDs for users in config instead of faked 
   • Fisheries demo repo: set DIDs for users in config instead of faked
   • Flow system - remove from triggers, use real ID
   • various kinds of tests - use in-memory repo

Note - UI impact (separate tickets):
- [x] Apollo InMemoryCache: user IDs for Account or AccountRef.
- [ ] Flow filters by account id instead of account name (separate ticket)
- [ ] Search by users - kamu-data/kamu-node#64

[sergiimk]

• AuthenticationRepository -> AccountRepository?
• store in database
  • (ADDED) let's add email from the beginning?
• CLI AccountService should use real AccountIDs
  • we should talk through this - I don't fully understand how this will work
  • I think we will hit complexity if we introduce persistent local accounts at this stage and perhaps it's better to have those only originate from .kamutokenstore when interacting with remote ODF repos