closes #419

Added support for an optional runtime config.json at the root of a built Open MCT instance using the Open MCT for MCWS Plugin. This allows built release artifacts to be configured at deployment time without rebuilding or updating recipe configuration through the Open MCT build tool. Common runtime overrides include mcwsUrl, namespaces, and other MCWS plugin options.

Example config.json:

{
  "mcwsUrl": "https://example.jpl.nasa.gov/mcws",
  "namespaces": [
    {
      "key": "mission",
      "name": "Mission Shared",
      "url": "/path/to/shared"
    },
    {
      "userNamespace": true,
      "key": "mission",
      "name": "Mission Users",
      "url": "/path/to/users"
    }
  ]
}

Config precedence is:
config.json > recipe config > plugin defaults
Only keys provided by a higher-precedence config override lower-precedence values. Omitted keys fall back to the recipe config, then plugin defaults.

Release artifacts include a config.example.json file. Users can copy or rename it to config.json and update its values if they want to provide runtime configuration overrides.