Make operator use new Scylla Manager client

[Choraden]

Description of your changes: The mermaid client was outdated. This PR updates it to the newest version.

• Scylla Manager swagger has been updated to this https://github.com/scylladb/scylla-manager/blob/9ad2186d6b6b922ac96ff7c08e45d4ba1b0dd31a/swagger/scylla-manager.json.
• Makefile for client generation has been created in mermaid client package. It follows Scylla Manager logic of generating clients https://github.com/scylladb/scylla-manager/blob/master/swagger/Makefile.
• New client has been generated, unnecessary old client code removed, old script to generate client removed.
• The operator has been adjusted to use new mermaid client.

[Choraden]

• Mermaid has been renamed to Scylla Manager
• Rules to update and verify Scylla Manager client have been moved to top level Makefile
• Swagger has been imported to vendor files

[Choraden]

@zimnx I've addressed your comments PTAL

[Choraden]

Changed names as suggested.

[Choraden]

@tnozicka I've addressed your comments PTAL

[tnozicka]

It's on my list for Monday, apologies for the delay. (if you we not to get a review pls ping me on Tue)

[Choraden]

@tnozicka ptal

[tnozicka]

This PR is being closed because of inactivity. Feel free to reopen if you plan to work on it.