Starcke/rename files

[starcke]

Rename data-extension-editor files to model-editor instead.

I also had to change the WebviewKind otherwise it failed when getting passed a message. Not exactly sure how that works or if there are other places we need to change.

Checklist

• CHANGELOG.md has been updated to incorporate all user visible changes made by this pull request.
• Issues have been created for any UI or other user-facing changes made by this pull request.
• [Maintainers only] If this pull request makes user-facing changes that require documentation changes, open a corresponding docs pull request in the github/codeql repo and add the ready-for-doc-review label there.

[charisk]

LGTM! The WebViewKind is used to figure out the locations of files, that's why you had to rename it.

[starcke]

LGTM! The WebViewKind is used to figure out the locations of files, that's why you had to rename it.

I thought it might, but didnt know where that happened, and the error was a bit confusing (it complained about an assertNever that apparently got hit).