Clean up default UX

[LukeTowers]

There are a lot of third party custom search providers included by default. In my opinion these should live within the plugins they are for (and if that's not possible, then at the very least the existence of the plugin they're for should be checked on the settings page before displaying that provider's options).

On another note, it would be ideal if the Settings model could pull defaults from a plugin configuration file (see how October implements it: https://github.com/octobercms/october/blob/master/modules/backend/models/BrandSetting.php#L77 - although you'd want to override the get method of the settings model in this case to load from config when an item is requested to retain full support for custom provider's settings). I try to avoid any database configuration in my projects instead utilizing configuration files and the environment file as this enables the code to configure itself without requiring any manual intervention on deployment to new servers.

[damsfx]

There are a lot of third party custom search providers included by default. In my opinion these should live within the plugins they are for (and if that's not possible, then at the very least the existence of the plugin they're for should be checked on the settings page before displaying that provider's options).

This par of the issue is resolved with #124 .