open local workspaces, files and folders in remote

[jonah-iden]

What it does

Implements #14574
This does 2 things regarding opening workspaces when connected to a remote.

1. It shows the list of local workspaces when executing open recent workspaces and allows opening them even when connected to a remote
2. It adds a new button to the file dialog when connected to a remote to show local files instead of the ones in the container. This then allows opening local folders and disconnecting from the remote by selecting one of these.

How to test

• Connect to a remote or dev-container.

• select file -> Open Recent Workspace...

• see the list should be equal to the list you see locally.

• Workspaces should be openable both dev-container and normal files/folders

• Connect to a remote or dev-container.

• use the file -> Open Folder... option.

• See there should be a new button Show Local

• Click to see a new file dialog opening showing the local file system

• Selecting the folder disconnects the remote and opens the workspace or opens a new window with the selected workspace (depending on settings)

Follow-ups

Breaking changes

• This PR introduces breaking changes and requires careful review. If yes, the breaking changes section in the changelog has been updated.

Attribution

Review checklist

• As an author, I have thoroughly tested my changes and carefully followed the review guidelines

Reminder for reviewers

• As a reviewer, I agree to behave in accordance with the review guidelines

[JonasHelming]

@jonah-iden What is the state of this PR?

[jonah-iden]

@JonasHelming Seems i've forgotten about this one. Still need adress the review comments. I'll try and take care of that next time i have some open-source time

[JonasHelming]

@jonah-iden Ping :-)

[jonah-iden]

@JonasHelming already requested a re-review. But thanks for the ping
@msujew ping :-) if you find some time?