NSIS Installer & GitHub Actions building

[rechyou]

This PR includes NSIS script and shell script responsible for generating file list, with some icons I made bundled in ArcCreateIcons.dll for file associations.
I've only tested this action locally with act, it will need manual test on GitHub.

There are several iteration on the script, old one had copy recursively and delete recursively command.
Later found out recursive deleting is quite dangerous and I was looking for solutions.
NSIS isn't able to track installed files nor remove only installed files, I had to write some shell script to generate list of files.

Beside listing files required to install, this script also handles optional user data install/deletions, NSIS/userfiles is a list of files where the file shouldn't be replaced or removed unless Remove User Data is checked in the installer.
NSIS/excludes is another file list for ignoring unnecessary files, should be self-explanatory.

These two files matches exactly from start to end, remove trailing space if you want to edit the list.