Add a new workspace creation URL parameter named editor-image

[l0rd]

Is your enhancement related to a problem? Please describe

In some cases a user may want to re-use the existing che-code or che-idea definitions and replace the injectro container image only.

But for such use case we still require to copy the existing che-code or che-idea yaml definition, change the injector container image and reference the URL in the editor URL parameter. This is an unnecessary and error-prone work.

Describe the solution you'd like

Add a new URL parameter named editor-image with the following behavior:

• The parameter is passed to the DevWorkspace generator that uses it to patch the <editor>-injector image.
• This should work together with the editor URL parameter too. For example:
  • editor-image=quay.io/mloriedo/che-code:copilot-builtin ==> replace the default editor image
  • editor=che-incubator/che-idea/next&editor-image=quay.io/mloriedo/che-rider:2023:2 ==> use the che-incubator/che-idea/next editor but replace the of the injector image

This is a subtask of the epic #22729

[ibuziuk]

Reopening due to missing documentation