[FEATURE] show specific progress from one level to the next

[Mittelblut9]

Description

This change adds a new configuration function to the setMinXP tool.
It will override the current calculation in _calculateProgress if set. It will calculate the difference between the minXP data and the requiredXP data.

To use this feature you just need to add setMinXP with your prevert value (for example: the XP to reach your current level).

Motivation and Context

I had the same problem as #144. I wanted to have a clean progress bar after each level. And to get this feature into the tool, I thought of a way to allow the user to reset the progress bar to a certain amount of xp.

Screenshots (if appropriate):

minXP = 7030
Above: Without minXP
Below: With minXP

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.

Closes #144