Use swagger api for delete single and multiple Service Accounts

[cesnietor]

It also catches correctly the error and shows it as snackbar.
It updates swagger yaml to be able to handle array of strings as input.

Test Steps

1. Go to User/Access Keys
2. Create a Key
3. Delete a single Key using the garbage icon
4. Key should be deleted and keys reloaded.

/// multiple Keys

1. Go to User/Access Keys
2. Create multiple Keys
3. Select multiple Keys
4. Click Delete Selected
5. Keys should be deleted and keys reloaded.

[prakashsvmx]

Verified. LGTM 👍

[cniackz]

LGTM, thank you @cesnietor plus all tests are passing!.