Impose push limits

[varmar05]

Let's limit the size of single push by imposing:

• number of files (do more pushes if hit)
• number of changes in diff file (geodiff split the work into multiple diffs, then multiple pushes)
• size of media file (not .gpkg) (sorry, not possible)
• size of gpkg (sorry, not possible, split manually into multiple gpkg files)
• size of diff file (geodiff split the work into multiple diffs, then multiple pushes)

And split the work into multiple pushes / files.

Actual limits to be defined.

Depends on MerginMaps/geodiff#224