fix listing of plugin components

Plugins may have one main component of a type or they might have
multiple of the same type in a subdirectory.

Sometimes they may have both. This is often the case f

fix listing of plugin components

Plugins may have one main component of a type or they might have
multiple of the same type in a subdirectory.

Sometimes they may have both. This is often the case for organically
grown plugin, commonly with helper classes where a helper.php exists
first only to be extended by helper/*.php files later.

This patch fixes the listing of plugin(components) by type in the plugin
controller.

It also adjusts bin/plugin.php to handle plugin CLI components.

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code style: line breaks

coding style: control flow whitespaces

coding style: function call spacing

codestyle adjustments: function declaration braces/spaces

codestyle adjustments: class declaration braces

Apply rector fixes to bin and toplevel

do no load disabled plugins in /bin/plugin.php

use envvars in shebang

moved plugin controller to Extension namespace

First go at moving the plugin classes into their own namespace

PSR2 adjustments for bin scripts

typo. capital P for class name

Introducing a new Plugin type: CLI

Now plugins can create their own command line interfaces. They are
executed through a single entry point in bin/plugin.php