implement a client to interact with Bitwarden servers directly

[maxlaverse]

Add a Bitwarden client as part of the project (see #26)

It's still experimental, but would offer the similar trade-off:

• [+] The provider would work out-of-the-box, without the need of installing the additional binary, making it's much easier to use.
• [+] The golang implement is much faster than the official client, because there is no need to spawn a NodeJS process on every command.
• [+] It gives more flexibility, opening up the possibility of creating attachment without having to write them on disk ([FEATURE] Content support for attachments  #146), or user management (FR: User management #134)
• [-] The provider becomes dependent to the server's implementation, which potentially means more work to support all existing flavors and versions.
• [-] The encryption is performed by the implementation which come with additional responsibility (e.g. not forgetting to encrypt any attribute with sensitive information) (more tests required)
• [-] The provider has to stay aligned with the official CLI and applications, in order for items encrypted by one tool to be decryptable by another tool. This means, encrypting the same fields for example.

The idea would be to release the feature as experimental first, until the test coverage is extended and people got the opportunity to report problems and concerns.