generialized simple custom components to simple custom <T>

main changes:

introduces SimpleCustom\, sounds nice when written.. e.g. SimpleCustom\
updated project to support latest C# language features (latest minor instead of lastest major language version)
got rid of weakreference and hooked into DataManager.Clear
extensions are now implemented with as little as possible code clones
most of database is now private (and internal) to avoid use from outside
component section name should only be part of the simple custom structure

BattletechModders / CustomComponents