Generate templating docs

[Guite]

The generator could create documentation (templating.md in docs folder) assisting in customising the templates.

Proposed structure:

Vendor/MyModule/Resources/views/base.html.twig

Purpose: this template does ...
It contains the following structure:

Variables

…
…

Blocks

{% block header %}

The header block is used in the following templates
…
…
The header block is extended in the following templates
…
…

{% block titleArea %}

...

Vendor/MyModule/Resources/views/MyEntity/index.html.twig

Variables

Blocks

...

cc @rallek

[rallek]

thanks :-)

[rallek]

Might be also some documents about available permissions are possible in another .md