Allow including a section with an id defined by the user

The idea is to allow the user to use the id macro as follows:

{{id name="my"/}}

== My Heading ==

And then use:

{{include reference="..." section="my"/}}

The rationale:

• Hard to find the id
• Not stable (if the heading title changes the include is broken)

See https://extensions.xwiki.org/xwiki/bin/view/Extension/Include%20Macro?editor=inline#HParametersdefinition