Extend the map file to be able to describe Push-Type registers

This is a child of #51.

Currently registers in mapped devices are implicitly poll-type. Some backends (uio, pcie) are able to deliver interrupts. This has to be integrated into the map files. Maybe the RegisterInfo object should be extended.

The extension must be able to describe different interrupts (numbered?), which can either be one register per interrupt line or one register which has the interrupt numbers that triggered as data (both should be possible).

The extension has to be synchronised with the MSK firmware group, which providers automatically generated map file.

• Propose a possible extension (or multiple) and have it (them) reviewed before implementing
• Extend the RegisterinfoMap::RegisterInfo and the map file parser
• Write tests for the new functionality

Afterwards it should be adapted in the uio branch so it can be merged into the master.

Start by reviewing the proposed map-file extension with the MSK firmware group, including the two interrupt representation options. Then inspect RegisterinfoMap::RegisterInfo and the map file parser, add tests for the chosen functionality, and adapt it in the uio branch so it can be merged into master.