[Feature]: Execution of custom scripts on Dockerfile and devcontainer.json

[kse3hi]

Description

As developer I would like to execute custom scripts in Dockerfile and devcontainer.json to be able to localize some behavior (e.g. specific proxy handling etc).

Currently all local changes will be re-written by velocitas init

This feature based on eclipse-velocitas/devenv-runtimes#49

Suggested Solution

ON_CREATE_EXTENSION_SCRIPT = ".devcontainer/extensions/on-create.sh"

if [ -e "$ON_CREATE_EXTENSION_SCRIPT" ]; then
    bash $ON_CREATE_EXTENSION_SCRIPT
fi

Alternatives

No response

Additional Context

No response

[BjoernAtBosch]

This is (at least partially) solved by #95: With that users can add repo-specific actions during devcontainer creation and post startup.
Not supported (still): Extending the Dockerfile with repo-specific steps.