Refactor Theia.cloud to Theia Cloud in code

[sgraband]

Currently we still have a lot of Theia.Cloud strings and comments in the code base.

[github-actions]

This issue is stale because it has been open for 90 days with no activity.

[jfaltermeier]

Keep open

[github-actions]

This issue is stale because it has been open for 180 days with no activity.

[jfaltermeier]

Keep open

[github-actions]

This issue is stale because it has been open for 180 days with no activity.

[lucas-koehler]

Many instances of this were adapted with #303 but I believe there are still some left.