Support more easily switching default shells in Che workspaces

[amisevsk]

Is your enhancement related to a problem? Please describe

It would be useful to be able to select the shell used for workspace terminal sessions. From brief testing, it appears the Che Code editor will default to using the login shell for the current user in /etc/passwd, but this can be overridden by using the $SHELL environment variable.

Describe the solution you'd like

Assuming it doesn't bloat the image size too much, the UDI image should include multiple shells (bash, zsh at minimum) with basic configurations (.bashrc, .zshrc, etc). Then, users could select their preferred shell by setting the $SHELL environment variable in their devfile.

A further step could be to enable selecting the shell prompt when creating the workspace, e.g. via factory parameter or dashboard UI element.

Note, in my testing, zsh requires a ~/.zshrc to exist on startup, or it will prompt the user to set one up on launch.

Describe alternatives you've considered

It's not necessary to do anything here; if the development image includes the desired shell, it's sufficient to set the $SHELL environment variable. This issue is more about making it convenient in default workspaces.

Additional context

To aid in testing, I've built quay.io/amisevsk/web-terminal-tooling:zsh as an image that includes both bash and zsh. Switching shells for Che Code can be tested by applying the following DevWorkspace to a cluster with Che installed:

kubectl apply -f https://gist.githubusercontent.com/amisevsk/986b628d26a61427fd2f679ddd414ee1/raw/8ee302f8ee4cece8787809e82229b289257c4521/shell-test.devworkspace.yaml

[l0rd]

Added to #20799

[che-bot]

Issues go stale after 180 days of inactivity. lifecycle/stale issues rot after an additional 7 days of inactivity and eventually close.

Mark the issue as fresh with /remove-lifecycle stale in a new comment.

If this issue is safe to close now please do so.

Moderators: Add lifecycle/frozen label to avoid stale mode.

[l0rd]

/remove-lifecycle stale

[che-bot]

Issues go stale after 180 days of inactivity. lifecycle/stale issues rot after an additional 7 days of inactivity and eventually close.

Mark the issue as fresh with /remove-lifecycle stale in a new comment.

If this issue is safe to close now please do so.

Moderators: Add lifecycle/frozen label to avoid stale mode.