XSD Schema generator for ViewHelpers improvements

[albe]

In order to import a ViewHelper namespace with autocompletion, the option to specify the xmlns:f="..." attribute on a tag is available. This allows the IDE to properly parse the f:... namespaces in templates without marking them as errors, and, if the according XSD schema is linked correctly, to support the user with autocompletion.

However, since the TYPO3Fluid standalone split, it is not easily possible any more, to generate a XSD schema for all f namespace ViewHelpers, because the tool only accepts a single PHP namespace to scan.

Also, the documentation for how to make use of that xml namespace import is scarce and the Kickstarter still uses the {namespace f=...} syntax for generating templates.

Actionables:

• schema generator should be capable again to handle TYPO3Fluid, currently it does not find any ViewHelpers for that PHP Namespace (see TASK: Include TYPO3Fluid for reflection #1637)
• schema generator should allow scanning multiple PHP namespaces for a single schema
• the documentation should be improved, to show how to properly make use of the xmlns:f import syntax, generate a schema and link it in common IDEs (PhpStorm)
• Adjust the kickstarter, to make use of xmlns imports
• Automatically generate an XSD schema on release for Typo3Fluid+FluidAdaptor and make it available versioned online, so it can be directly linked via f:schemaLocation="https://..."