cvmts: replace jpeg-turbo native module with new rust module

This module also does threadpooling internally, so we don't need Piscina anymore (which I'm pretty sure was actually bottlenecking.)

.gitmodules

@@ -1,6 +1,3 @@
 [submodule "nodejs-rfb"]
 	path = nodejs-rfb
 	url = https://github.com/computernewb/nodejs-rfb
-[submodule "jpeg-turbo"]
-	path = jpeg-turbo
-	url = https://github.com/computernewb/jpeg-turbo