Import support from command line.

[subdavis]

For users that prefer to stay away from the web vault and for scripting bulk operations.

Benefits:

• unencrypted data never has to touch a web browser
• self-hosting the backend requires extra effort
• for people who use a non-standard backend (I'm currently in love with https://github.com/vvondra/bitwarden-serverless but this is also true for whoever uses the ruby implementation) there's a fair amount of extra work to get the vault running.

It would be awesome to support doing this from the CLI, since 90% of the work is already done in jslib.

I intend to take on this work and implement it as follows:

1. Recreate the generic import logic from web in jslib as importer.service.
2. wrap that service from the CLI just like export does.
3. open jslib pull request, and once it's closed and released, open the cli changes as another.
4. go back and refactor web to use the new importer service, and submit as a separate pull request.

Please let me know if you have reservations about any of that.

[kspearrin]

Sounds good to me.