add kamictl debug: list open fids on every ongoing connection while here also fix the imsg retrival loop

Merge branch 'portable' Trying to maintain two branches was impossible at this stage for me alone, so I'll recognize my stupidity and merge the portable branch into the main one. The repository will build using autotools.

fix build on linux

restructure project and switch build system use by default the OpenBSD mk infrastructure to build and test all the kamid components.