Resolve convoluted video mode handling

[sy2002]

This needs some research at first and then, depending on the research a refactoring or not:

We have a package that defines our video modes: video_modes_pkg.vhd

We define a constant video mode vector: https://github.com/MJoergen/C64MEGA65/blob/develop/M2M/vhdl/framework.vhd#L245

And then, a few levels down the pipeline, we use hardcoded positions of this very vector to map back to the very constants from our video_modes_pkg.vhd: https://github.com/MJoergen/C64MEGA65/blob/develop/M2M/vhdl/av_pipeline/digital_pipeline.vhd#L184

It is unclear why and how this rather convoluted structure evolved including those hardcoded things where created in the first place, why framework.vhd needs a new array of constants, why we are mapping back and forth also here:

https://github.com/MJoergen/C64MEGA65/blob/develop/M2M/vhdl/framework.vhd#L430C65-L430C84

using constants that are also defined in our video_modes_pkg.vhd.