Bump nwn resources from 36.12 to 37.15

Downgrade ruby back to 3.0.2 for nwn-lib compatibility

The YAML parser 'psych' in 3.1.x is incompatible with the output of nwn-lib, throwing runtime errors on YAML syntax when extracting. We're stuck on 3.0.2. The next release should upgrade to neverwinter.nim, given YAML support.

Use ruby 3.1.5 for nwn-lib compatibility

The ubuntu image had ruby 3.3 installed which caused runtime errors on use of the deprecated 'File.exists?' in nwn-lib (calling nwn-build extract).

Ruby is the main runtime dependency of this tool, so we base ourselves on one of the official ruby images.

Replace File.exists? with File.exist?

Forgot one with a3497c3.

Reduce chance of naming conflicts on scripts dir for container builds

When mounting a volume, if there was a 'scripts/' dir in the mounted folder then nwn-build.rb would fail on piping output through 'scripts/truncate_floats.rb'

Expose 'nwn-gff --encoding' flag to config

Upgrade to gem ffi 1.9.25

Merge pull request #16 from nwngracken/master

Set build.rb to be executable

Place nwn-build on global PATH

build.rb install symlinks to HOME/bin. Dockerfile is built as root, so /root/bin is not on path when UID changes.
Prefer /usr/local/bin

Document how to use nwn-devbase v2