Add regex matching rules for large groups of uniform line icons

[echtnurich]

I think it would be a big time-saver to allow regex rules for matching a lot of lines to the same design icon.

For example, i've managed to break almost 300 Bus and Ferry lines that share a number space down into 6 rules:
echtnurich/line-colors - [proposal-regex] /line-colors.csv

I've used regex101.com to validate these.
It also helps with understanding the use of named matching groups to extract the line (or operator) from the hafasLineId.

I'm not sure what syntax would be optimal to actually implement, so for now I'm going to leave it at the proposal for further discussion.

Examples

Primary Metrobuses

^5\-hvv(?'operator'hha|vhh)\-(?'line'\d)$

• 5-hvvvhh-1
• 5-hvvhha-7

Secondary Metrobusses

^5\-hvv(?'operator'hha|vhh)\-(?'line'[1-2]\d)$

• 5-hvvhha-17
• 5-hvvvhh-21

Citybuses

^5\-hvv(?'operator'hha|vhh)\-(?'line'[0-5,7-9]\d\d)$

• 5-hvvhha-261
• 5-hvvvhh-286

Nightbuses

^5\-hvv(?'operator'hha|vhh)\-(?'line'[6]\d\d)$

• 5-hvvvhh-601
• 5-hvvhha-607

Expressbuses

^5\-hvv(?'operator'hha|vhh)\-x(?'line'\d{1,2})$

• 5-hvvvhh-x3
• 5-hvvhha-x35

Ferries

^6\-hvv(?'operator'had)\-(?'line'[6-7]\d)$

• 6-hvvhad-62
• 6-hvvhad-73

[ghost]

especially for hamburg, this would be a nice addition.

hamburg buses usually don't use different line colours, except for some maps online.

a wildcard for hvv routes would be kinda nice, but that might need some discussion imo.

MetroBus/city buses/regional buses

• red on bus stops
• hexagon

night bus

• black on bus stops and, afaik, maps
• hexagon

express buses ("XpressBus")

• green on bus stops
• hexagon

ferries

• blue everywhere
• trapezoid

(and, of course, that'd be a nice addition for networks without colour usage)