don't add gmid as organisation when generating the certificate, and set the version to 3, so it's compatible with java/android clients. Found by Gnuserland, thanks!

saves some bytes of memory and removes the limit on the maximum number of vhosts and location blocks.

use imsg to handle ALL kinds of IPC in gmid. This simplifies and shorten the code, and makes everything more uniform too.

Include gmid.h as first header in every file, as it then includes config.h (that defines _GNU_SOURCE for instance). Fix also a warning about unsigned vs signed const char pointers in openssl.

on fedora 33 the BIGNUM type is opaque. Allocate always to avoid headaches.

keep mark_nonblock in utils.c, as otherwise the build for the regress suite will fail (mark_nonblock needs fatal which is in gmid.c, and we can't link gmid.o with the regress suite...)