Adding min/max threshold configuration

* Check for min/max values set for auto payouts
* Display error messages to the user
* Sanitize values just in case we fall through the validation
* Updated template and class
* New configuration option added! Update your local configs!

Fixes #108
Add new threshold display to template

Forgot to add the template files that adds configurable thresholds
Merge pull request #110 from TheSerapher/issue-108

Issue 108