Outdated draft cubes must be removed?

There are many draft cubes. Each new cube update creates a new draft class instead update existing one.

Examples:
* MTGO Legacy Cube 2016 September — must be MTGO Legacy Cube
* MTGO Vintage Cube 2013 — must be MTGO Vintage Cube
* etc


I don’t think anyone use that old versions. So xmage must contain a single draft cube with dynamic name (name must contains last updated info —so no need to update server config after each new cube version).

TODO:
* [x] make cube name dynamic (loaded from a class, not from config);
* [ ] combine all updated versions of the cube to single file with single cube (latest version only);
* [ ] delete all old unused draft cubes (keep only latest draft cube version);
* [ ] make sure new version will work with old configs (if it contains non existing draft cube records).

No files or tests are named in the issue. Start by locating the draft cube definitions, their configuration references, and the code that loads cube names; then trace how old configuration records are handled. Done means only the latest version remains, its name reflects the latest update, and old configurations still work.

Written by the indexing model from the issue text.