software/slapos-master: fix slapos master to add parameters required for apachedex and mariadb promise

/reviewed-on nexedi/slapos!215

also update groonga 7.0.5 and mroonga-7.05.

@Tyagov  @luke 

/reviewed-on nexedi/slapos!212

Instead of templating python code, make it static and parameterize it
with parameters.

kernel.json can pass default ERP5 url, which is (dirty) read by
ERP5kernel. Additionally ERP5kernel.py is just linked into kernel
directory, which simplifies debugging.

Note: This commit is still dirty, but it prepares ERP5kernel.py to be
      packaged, thus there is no reason to make more changes and
      cleanup.

/reviewed-on nexedi/slapos!206

grep '----- something' fails because of the '-' character
used for passing options:
grep: unrecognized option '----- something'
so only grep for the string 'something'

on the SlapOS's host, as required to chroot in the build
environment cros_sdk

configuration files

Automate ebuild revision numbers.
Reactivate testing.

"Scoreboard is full,not at MaxRequestWorkers" errors in monitor instance logs.

See https://httpd.apache.org/docs/2.4/mod/mpm_common.html#serverlimit,
which indicates to set MaxClients rather than ServerLimit.