Add SSH Keys to the Vault

[spheppner]

Is your feature request related to a problem? Please describe.
Not directly related to a problem, but it would be nice to have the option of adding SSH-Keys to the Vault as well.

Describe the solution you'd like
Next to being able to store passwords, add a new type of item in the Vault, which are SSH-Keys. They could also be used via the Desktop application.