Feat: add AdvancedParse plugin for parsing strings with a custom format

[BePo65]

Add the AdvancedParse plugin for parsing strings with a custom format.

Add a short documentation for this plugin and a rudimentary index page for all documentation pages.

Works also with the utc plugin.

Changed the core parsing implementation and the utc plugin to remove the tight coupling between these modules. Added an 'official' method (dateFromDateComponents) to the core module that creates a javascript Date object from the date components. This method is overloaded in the utc plugin to handle utc dates.

In the LocalizedParse plugin (work in progress) this plugin will get a method to extend the used parsing tokens (e.g. required by the timeZone plugin).