Please consider notion of 'init container' for devfile

[RickJWagner]

Devfiles are used by Che and CodeReady Workspaces. Some users have sophisticated needs that would benefit from some scripted initialization.

Example: A Che user wants to do a Java/Maven build with a custom settings.xml file (very common). Per the product documentation, a Secret can be used to mount the settings.xml file. The user wants to supply the Secret as an early step in the Workspace creation. (Currently, there is no opportunity to do this through a devfile-created workspace. The workspace will start before the user has a chance to make a Secret, thus this path to getting a custom settings.xml file is unavailable.)

Please help by considering allowing some notion of an 'init container' or other ordering or prioritization for some directives so initializations can be done.

[sparkoo]

Is this for devfile v1 or v2? In case of v1, I think this issue belongs to https://github.com/eclipse/che/issues, in case of v2 it should go to https://github.com/devfile/api/issues