Create an "encrypted" Repository

[ryardley]

Currently we need to separately encrypt and save data here:

in keyshare:
https://github.com/gnosisguild/enclave/blob/95af527d03cb4ccc760d30aad4a3d2761d7c15ba/packages/ciphernode/keyshare/src/keyshare.rs#L54C1-L54C62

In net:
https://github.com/gnosisguild/enclave/blob/ry/180-save-keypair/packages/ciphernode/net/src/network_manager.rs#L78-L92

In the commands:

https://github.com/gnosisguild/enclave/blob/main/packages/ciphernode/enclave/src/commands/wallet/set.rs#L9-L16

We also have a PR in the works for encapsulating stored data as auto persistable: #189

We should probably create an encrypted repository to automatically encrypt data sent and received from it to it using a given cipher and have that available on the repositories object.