feat: slim project config

[dennismeister93]

This PR will slim our .velocitas.json to something like:

{
    "packages": {
        "https://github.com/eclipse-velocitas/pkg-velocitas-main.git": "v0.0.x",
        "https://github.com/eclipse-velocitas/devenv-devcontainer-setup.git": "v2.0.0",
        "devenv-runtimes": "^v2.0.0",
        "https://github.com/eclipse-velocitas/devenv-github-templates.git": "v1.0.*",
        "https://github.com/eclipse-velocitas/devenv-github-workflows.git": "v5.0.0"
    },
    "components": [
        "vapp-core-python",
        "devcontainer-setup",
        "sdk-installer",
        "runtime-local",
        "runtime-kanto",
        "deployment-kanto",
        "github-templates",
        "github-workflows"
    ],
    "variables": {
        "appManifestPath": "./app/AppManifest.json",
        "test@devenv-runtimes": 123,
        "blabla@runtime-local": "huhu",
        "githubRepoId": "<myrepo>"
    },
    "cliVersion": "v0.0.0"
}

[doosuu]

lgtm