Fix usage of Block.ModuleSource

[BSick7]

Information about the module on a Block is no longer useful.
However, we cannot remove it yet because it's still in use across the UI, CLI, and (maybe) engine.

We need to fully deprecate usage of:

• ModuleSource
• ModuleSourceVersion

We also have Type that is useful for filtering in the UI (which modules can be used, which blocks show in the right context).
We need to decide how to handle a block switching types.

• Should it be allowed? (Maybe only if all workspaces have no infra)
• If it is allowed, should it change with WorkspaceTemplate?
• What other gotchas emerge?

TODO

• Test nullstone status (app and app workspace)
• Test all workspace commands (deploy, push, ssh, etc.)