Test with new worksapce image

Issue - Build workspace base image and use it as base f... (gitlab#524214 - closed)

What does this MR do and why?

Update web ide workspace image to use our latest workspace base image after the MR.

Then we also try to do below things together:

• Switch to use mise from asdf in workspaces (asdf should still be usable locally)
• Add .mise.toml (For mise, this file takes priority over .tool-versions)
• Replace scripts/initialize-workspaces.sh with post-start script in devfile

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Before	After

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