Hello

is there any detailed documentation regarding the configuration?

So for example:

PointsPerHit": {
      "A": 30,​

Whats 30 points? 30 points of 100 or 1000?
So for a level up someone need to hit a tree 4 times or 34 times?

ResourcePerLevelMultiplier": {
      "A": 2.0,​

The multiplier 2.0 means? Maybe in percent?!

How many points you need per level depends on the level: 

110*level*level-100*level

To get to level 2, you need 8 hits.

https://www.wolframalpha.com/input/?i=graph+110*x*x-100*x++x+from+1+to+40

Merged post

A note that the progression is actually linear because the points don't reset when a player level up which leads to some unneccessary code, for example this:

long getPointsLevel(long points, string skill)
{
var a = 110;
var b = 100;
var c = -points;
var x1 = (-b - Math.Sqrt(b * b - 4 * a * c)) / (2 * a);
if ((int)levelCaps[skill] == 0 || (int)-x1 <= (int)levelCaps[skill])
return (int)-x1;
return (int)levelCaps[skill];
}

How many hits you need with 30 points:
7.33*level*30+10