Cannot specifically identify which key to delete with the deleteSshKey mutation

[cdchris12]

Describe the bug

The deleteSshKey mutation only allows for selecting an SSH key based upon the key's name, which is not a globally unique key in the database. As a result, it is not possible to specify exactly which key Lagoon should delete with this query.

To Reproduce

Steps to reproduce the behavior:

1. Add two different keys to the API with the same name
2. Check the ssh_keys table in the api_db to verify that both keys exist there with the same name as expected.
3. Attempt to remove only one of those keys using the deleteSshKey mutation

Expected behavior

Lagoon should allow the deletion of an SSH key based on something which can be guaranteed to be globally unique, such as the public key string itself or the id of the ssh key in the db, as that auto increments to ensure uniqueness.

Additional context

Quasi-related to #2085 , though I feel this is different enough to warrant its own issue.