Feature request : plant flag on a specific biome contract/prerequisite

[Goufalite]

The stock "plant flag" contract is a joke. At this moment I have Gilbert Kerman stuck on a "permanent base" on Duna and I ask him to get out and plant/remove a flag from time to time to gain a lot of funds...

Suggestion:
New contract or pre-requisite to a biome visit to plant a flag on a specific biome, already explored or not (later prefered of course).

Why:
I wanted to write my own contract pack just to address this problem of "generic flag planting => yay funds!", and told myself "hey what about those who ask to take a measure near or on a planet".

I then found your mod which addresses the later, and the contract configurator creator asked for people to not just create single contract packs. Hence my request here.

I'll try to do a pull request when I have time but my situation doesn't allow a good testing situation. Also I don't know well enough contract configurator to do this...

Balancing/Reason:

• Obviously fixing and giving a better challenge for the stock "plant flag" contract
• Marking a biome is a first step before sending a ship with a lot of science instruments.
• If a Kerbal is alone on a rover seat, he/she cannot plant a flag unless a command pod is nearby, so this is challenging since a full station must move to the biome to plant the flag.
• Encourages biome exploration, especially if you have one time science instruments like the mystery goo.

Thank you!