This is the first step of improvements over keypairs/keycards/accounts.
- `SyncKeypairFull` protobuf removed
- `SyncKeypair` protobuf is used for syncing all but the watch only accounts
- `SyncAccount` is used only for syncing watch only accounts
- related keycards are synced together with a keypair
- on any keypair change (either it's just a keypair name or any change made over an
account which belongs to that keypair) entire keypair is synced including related keycards
- on any watch only account related change, that account is synced with all its details
Changes applied here introduce:
- improvements to sync wallet accounts among devices (including all account types)
- backing up wallet accounts to and fetch them from waku (an information about received
wallet accounts is sent via `waku.backedup.wallet-account` signal to a client)