Feature: Set default company secondary colour for new games

[M3Henry]

Motivation / Problem

The primary company colour for new games is a config option. However the secondary colour always assumes the same as the primary colour. It would be nice to be able to set both independently.

Description

Add secondary company colour to config and use that in new games if set. Allowed options are:

• "Same as Primary CC" (default)
• "Colour"...

Limitations

Options could include:

• "Random (not same as Primary CC)"
• "Completely Random"
• "Complementary of Primary CC"
• "Shade / Tint of Primary CC"

Other things that might be interesting?

• Generate a full set of random 1CC/2CC liveries: by group and/or type
• Also use setting for companies started during multiplayer
• This only sets the Global secondary company colour, going more granular might be good, or might not be.

Checklist for review

• This PR touches english.txt or translations? Check the guidelines

[2TallTyler]

Do you plan to add the other colour options (tint, complementary, etc) in this PR, or leave them for later? I think this stands alone, but don't want to be hasty with an approval. 😃

Changes requested