Update gl to v5.x

[dhritzkiv]

I noticed that gpu.js (and by extension brain.js) still use v4 of gl. v5 fixes some build issues users were having on macOS and linux, and upgrades node-gyp, which uses python 3 (saw a HackerNews thread about python 2.7 being a blocker for them installing brain.js)

Notes:

• Node 10 is no longer supported (it may or may not work). Node 12 is the oldest supported version (for now)
• Node 18 doesn't build properly, but that's not a regression. It should be resolved by the time 18 is LTS (September?)
• python 3 is used to build from source
• many build issues have been resolved (meaning lots of gpu.js/brain.js issues can be closed)
• prebuild-install supports npm 7
• by installing gl v5, the package-lock file was also updated, but it looks like it hasn't been updated in some time.
• some (13) of the tests fail, but I think that's specific to my machine?