Extend the PluginManager with a management UI

[billz]

For its initial release, RaspAP's PluginManager requires users to follow several manual steps to clone a plugin, update permissions, apply configurations and so on.

A future enhancement would allow users to upload a plugin archive enable plugins via a management UI within RaspAP. The application would then unpack the archive, inspect a manifest and perform a limited set of actions to install and activate the plugin. Once installed, the UI would display a list of active plugins and (optionally) permit a user to activate/deactivate them.

To this end, the SocksProxy plugin includes a manifest that encapsulates some basic details about the plugin, its dependencies, system configuration files, sudoers permissions, etc.

Would a plugin management UI be a useful addition to the project?

[billz]

Currently in progress RaspAP/raspap-webgui#1717

[billz]