Add information to skill about experience points scaling.

[Naerriel]

People may want to plan different amount of time to spend on different skills and it would help people more to see their involvement if experience needed to get to a certain level would depend on % of involvement given, instead of overall involvement given.

Current level-up system is based on assumption that people want to spend 100 minutes weekly on a skill.
Solution to this issue would be additional information to each skill "How many minutes a person wants to spend on a skill weekly?"

Problem to solve: How to store this additional information about skill?
Maybe by "skillName" + "Exp" we would store skill exp,
and by "skillName" + "Planned" we would store weekly plan?
Maybe store a table by name "skillName" which would contain all necessary information?