- Use `xz-utils` component for log file compression
- Fix some stacks and software releases to use the logrotate stack instead of re-creating it:
  - `software/caddy-frontend`
  - `stack/resilient`

/reviewed-on nexedi/slapos!508

Use xz instead of gzip.
Also put the cron script in etc/service instead of etc/run (to have the
"cron-on-watch" process)

Building Bison 3.3.2 now requires automake.

OpenVPN fails to build on Debian testing because
net-tools is no longer provided by default.

/reviewed-on !534

in apache frontend, we have been using:

```
LogFormat "%h %l %{REMOTE_USER}i %t \"%r\" %>s %b \"%{Referer}i\" \"%{User-Agent}i\" %D" combined
```

The %l is (from mod_log_config docs): Remote logname (from identd, if
supplied). This will return a dash unless mod_ident is present and
IdentityCheck is set On.

In the case of apache frontend, it was always a - . This is missing in
caddy frontend and our existing log processing tools (apachedex) cannot
be used on frontend logs since we switched to Caddy.

/reviewed-on nexedi/slapos!530

dict in headers is smallcase, so it was never working in reality.

Added assertion which proves that the ATS is serving stale content in case if
the backend does not work, according to RFC5861.

It is beleived that stale-while-revalidate will work the same way, but it is
much harder to test, thus it is not done directly.

Adapted configuration and instantiation to ATS 7.

Deployment:
 * traffic_line has been replaced with traffic_ctl
 * access log, of squid style, is ascii instead of binary, to do so
   logging.config is generated
 * ip_allow.config is configured to allow access from any host
 * RFC 5861 (stale content on error or revalidate) is implemented with core
   instead with deprecated plugin
 * trafficserver-autoconf-port renamed to trafficserver-synthetic-port
 * proxy.config.system.mmap_max removed, as it is not used by the system anymore

Tests:
 * As Via header is not returned to the client, it is dropped from the
   tests, instead its existence in the backend is checked.
 * Promise plugin trafficserver-cache-availability.py is re enabled, as
   it is expected to work immediately.

as suggested by Jerome on b26ae6b3

old URL doesn't exist anymore

Do not change any defaults regarding 1.9, 1.10 and 1.11.

Usually the slapos.core on nodes is installed with slapos.libnetworkcache,
so do the same for testing environment, so shacache can be used during
installation.

It is better to have automation similar to previous implementation by
default.

AIKC - Automatic Internal Kedifa's Caucase CSR signing, which can be triggered
by option automatic-internal-kedifa-caucase-csr.

It signs all CSR which match csr_id and certificate from the nodes which needs them.

csr_id is exposed over HTTPS with short living self signed certificate,
which is transmitted via SlapOS Master. Thanks to this, it is possible to
match csr_id with certificate of given partition and take decision if it shall
be signed or not.

This is "quite secure" apporach, a bit better than blidny trusting what CSR
to sign in KeDiFa. The bootstrap information, which is short living
(certificates are valid for 5 days), resides in SlapOS Master. The csr_id
is not directly known to SlapOS Master, and shall be consumed as fast as
possible by frontend cluster operator in order to sign CSR appearing in
KeDiFa caucase. The known possible attack vector requires that attacker knows
caucased HTTP listening port and can hijack HTTPS traffic to the csr_id-url
to get the human approve his own csr_id. The second is hoped to be overcomed
by publishing certificate of this endpoint via SlapOS Master.

Unfortunately caucase-updater prefix is directly used to find real CSR, as the
one generated is just a template for rerequest, thus csr_id would be different
from really used by caucase-updater.