Rework the Deployment Model

[Lisias]

KSPe evolved into something way bigger than the original KSPAPIExtensions from Swamp-ig.

It's a whole new things that happens to have the legacy KSPAPIExtensions embedded as a discrete (and optional) component.

For wide use in the wild, including proper support on CurseForge, the following tasks should be carried on:

• Rename the installation dir to 000_KSPe
• Get rid of all mentions of KSPAPIExtensions other than the legacy support implemented on the KSPAPIExtensions.dll - this thing is called KSPe.

This task blocks #41

[Lisias]

This task was carried out for some time now. So I'm closing it.