Convert this module into a runtime package

[wpscholar]

The following is required to convert the module into a normal package:

• Remove the code from the bootstrap file that handles the module registration on the plugins_loaded hook. Instead, just initialize the Runtime class directly.
• Rename the repository from wp-module-runtime to wp-runtime.
• Update the composer.json file package name (see https://github.com/newfold-labs/wp-module-runtime/blob/trunk/composer.json#L2).
• Update any other references to the old repository or Composer package name.