[WIP][POC] Add PatchConfigurator

[kbond]

A configurator to allow patching existing files.

// manifest.json
{
    "patch": [
        {
            "file": "assets/app.js",
            "position": "end", // appends to end of file
            "value": "\n// activates all of Bootstrap's JavaScrip functionality\nimport 'bootstrap';\n"
        },
        {
            "file": "assets/styles/app.css",
            "position": "start", // prepends to start of file
            "value": "@import \"~bootstrap\";\n"
        },
        {
            "file": "templates/login.html.twig",
            "position": "after_target", // adds after "target" below
            "target": "</button>",
            "value": "\n        <a class=\"btn btn-link\" href=\"{{ path('reset_password_request') }}\">Forgot your password?</a>\n"
        },
        {
            "file": "config/packages/twig.yaml", // manipulate yaml
            "target": "twig.form_themes[]",// adds to this config array (creates path if it does not yet exist)
            "value": ["bootstrap_5_layout.html.twig"]
        },
        {
            "file": "package.json", // manipulate json
            "target": "devDependencies[]",// adds to this array/object (creates path if it does not yet exist)
            "value": {
                "boostrap": "^5.0.0",
                "@popperjs/core": "^2.0.0"
            }
        }
    ]
}

TODO:

• must be queued and run at end
• patch json
• patch yaml
• tests

[kbond]

Closing in favor of #975.