Port remaining cachepot changesets

[drahnr]

There are a few viable features, yet to be ported from #paritytech/cachepot :

• Support running dist compilations in unprivileged scenarios paritytech/cachepot#128 ~> Custom sandboxing implementation as linux usernamespace calls - port cachepot/#128 #1628
• Handle signals in dist paritytech/cachepot#139 ~> Handle signals in dist mode #1629
• Prepare for running the dist suite as an unprivileged user paritytech/cachepot#140
• rouille -> warp paritytech/cachepot#131
• rename internal components paritytech/cachepot#134

I plan on porting them in the next few weeks