Add devfile for Web IDE

Add devfile for Web IDE. This will allow us to create a workspace directly from this repository.

Right now, I'm adding a temporary container image that we've built. Let's start with this and make a more formal process on how to build this image - not just for this project but for GitLab as a whole.

The added devfile is basically saying the following

• Let's create a container component named web-ide using the image registry.gitlab.com/gitlab-org/remote-development/gitlab-remote-development-docs/debian-bullseye-ruby-3.2-node-18.12@sha256:485ea8a6eaf66a19b7736a20819da9aa7e883545fce84a5faedf2fe7f7249656 i.e. SHA256 for the tag rubygems-3.4-git-2.33-lfs-2.9-yarn-1.22-graphicsmagick-1.3.36-gitlab-workspaces
• It will expose an endpoint named example-app on port 8000 which will be accessible on https and will be secure(protected by some authentication i.e. OAuth)

You can view the devfile schema at https://devfile.io/docs/2.2.0/devfile-schema

P.S. - GitLab Web IDE would be the first project to be onboarded for Remote Development 😉