Ability to get current page number

[manfromarce]

Is your feature request related to a problem? Please describe.
I need to show different header / footer on even and odd pages. While the ShowIf() method allows to specify a condition, I didn't find a way to get the page number (without rendering it).

Describe the solution you'd like
A way to retrieve the current page number and, if possible, the page number within the current section/page set.