Rewrite and restructering

Mainly rewritten the tex_to_yaml conversion. I used regular expressions (also called regex) to simplify the parsing of the table data. Even though these expressions can get quite complicated, they allowed for a simplified workflow. I also reworked the argparse arguments, as many options were obsolete (we always want to sort and clean the data and it does not really make sense to provide arguments that are not recommended).

I also reworked the argparse arguments in the sense that only --ind_col is required, with the remining arguments being purely optional. The determination of ind_row is now handled automatically in the same way as data_start and data_end. However, it is still possible to use --ind_row for cases where this automatic detection does not work. I also added the arguments --data_start and --data_end for the same reason. The script now also automatically inserts placeholders for names, labels and units if no input argument is given.

Other to that, Julian (@jboelhauve) and I reworked a bit the structure of the project. Examples are e.g. now not part of src anymore, with each example being provided with an example execution command. Julian also simplified the README.