co⚡e: Sparkplug™ MQTT edge

[#144] continue work towards FB_WStringBuilder larger string size
Append, Delete, Find, InsertAt have been modified
No testing done yet
The other methods still can be checked

Sparkplug Development Lib v1.4.2.18 changelog, still work in progress
* changed Project Information

* Changed FB_MetricFileTransfer.ReturnFileName (Maybe it should return the filetransfer properties (filesize, filename, full path, any other metadata on the file?)

* Changed FB_StringBuilder as preliminary unittesting shows it contains bugs
regarding WSTRING(80) which is nonsensical for WSTRING

* FB_StringBuilder main body
* FB_StringBuilder.append
* FB_StringBuilder.delete
* FB_StringBuilder.find
* FB_StringBuilder.insertat
* FB_StringBuilder.len
* FB_StringBuilder.mid
* FB_StringBuilder.replaceat
* FB_StringBuilder.right
* FB_StringBuilder.tostring
* FB_StringBuilder.towstring
* Changed ILimitedStringBuilder, EXTENDS __SYSTEM.IQueryInterface
* Changed IStringBuilder, EXTENDS ILimitedStringBuilder
* Added Function ReturnFileName as this function seems to be useful enough
* Added accompanying unittest for FB_StringBuilder in seperate project, also work in progress

v1.4.2.8 library changed identity to:
co⚡e: Sparkplug™ MQTT edge and host
CODESYS + MQTT + Sparkplug = 'Plug & Play' IIoT