add a few missing libraries and a note for the need of $FONTCONFIG_FILE

other sections are supposed to use this macros and define a part. Having
a default here is useless and maybe confusing

This reverts commit 80673c8c.

All testnodes should have been updated by now, so this commit is no
longer needed.

/reviewed-on nexedi/slapos!419

/reviewed-on nexedi/slapos!416

/reviewed-on nexedi/slapos!415

/reviewed-on !408

isp data is from https://www.whoismyisp.org/ip
cn-t for china telecom, default one if isp is other value
cn-m for china mobile
cn-u for china unicom

fix rst syntax - second try

fix markdown syntax

from nexedi/slapos!408 (comment 66703)

as always, using wrapper is easier and more flexible

also use a real bash and not busybox

   bzip.org don't exist anymore, download from fosseis is ok as the md5sum guarantee we still get the same file.

/reviewed-on nexedi/slapos!406

LIBPCRE1_JIT is required to compile git-2.17.1, so we enabled jit in pcre component. Another solution will be to compile git with NO_LIBPCRE1_JIT=1 and keep jit disabled in pcre.

when accessing gitlab URL ex: lab.nexedi.com from renderjs, URL is blocked because there is no CORS.
Set cors header directly in nginx configuration, so that it's not required to create custom slave frontend configuration to include Access-Control-Allow-Origin

Gitlab-ce upgraded to version 8.17.8 with required gitlab-shell version 4.1.1-1 and gitlab-workhorse version 1.3.0.
Configurations and wrapper upgraded to work with the current version.

Each slave rejected by the frontend will report back detailed information
to slave requester in key request-error-list being [json_list_of_found_errors]

Master partition reports information in rejected-slave-dict instead of
rejected-slave-list, which is defined as:

{
  'slave_name': '[json_list_of_found_errors]'
}

Globals were needed to distnc between caddy-frontend and apache-frontend.

kill -SIGXXX works only in bash and not when the shell is e.g. dash, for
example:

	$ kill -SIGUSR1 1
	/bin/sh: 2: kill: Illegal option -S

This way log rotation for slapproxy.log & friends was not properly working.

Fix it by using `kill -XXX` form which is supported everywhere.

/reviewed-on !402