Refactor help files

The help files have a lot of information that is the same for all of them (such as the provider and travel mode).
Currently, they have to be synced manually, which is cumbersome and prone to errors.

I can see two ways to prevent that:
* refactor common info into a separate file and read from there during the `read_help_file()` function as well
* use some form of templating engine
* either to do templating during processing
* or before upload