R Dev Container: Connect local Positron IDE to Gitpod via SSH

[hturner]

This issue explores the open questions on r-devel/r-dev-env#193 (comment).

We have established the following procedure for connecting a local Positron IDE to the R Dev Container running on Gitpod:

1. Start the Dev Container as a Gitpod workspace.
2. From https://gitpod.io/workspaces, click on the three dots next to the workspace to expand the menu, select Connect via SSH. If necessary set up an SSH key. Copy the command, something like (modified from actual!):

   ssh 'rdevel-rdevenv-13ik2dk36zo@rdevel-rdevenv-13ik2dk36zo.ssh.ws-eu116.gitpod.io'

   and paste it somewhere for reference.
3. In Positron Settings, search "remote host" and check the box under "Positron: Remote Host Experimental".
4. From the command palette, select Remote-SSH: Connect to Host. When prompted, enter the user@hostname in the SSH command copied from Gitpod, e.g.

   rdevel-rdevenv-13ik2dk36zo@rdevel-rdevenv-13ik2dk36zo.ssh.ws-eu116.gitpod.io

5. From the explorer, select Open folder, when prompted, enter workspace/r-dev-env. The environment variables are set as expected and the remote folder opens as a usual folder, so we can easily open the remote files

The open questions are:

Some open questions:

1. Can we open straight in the correct folder? (workspace/r-dev-env)
2. How much of the tutorials will still work? (We expect that the scripts to update R won't work as Positron doesn't use an R terminal the same way as VS code.)
3. Assuming we can build R, is there a way we can get Positron to find it, to run in the Positron console?

The last question is the most crucial for us to be able to make this a user-friendly option. But it could still be interesting to be able to build R in the terminal and work with the built R there, whilst being able to edit test/source files in Positron.