All data related to the instance shall be in the instance itself, and as
temporary files are crucial for caucase, force the macro user to set the
location.

See merge request nexedi/slapos!987

This option takes a string representing a valid JSON object and
forwards the corresponding python dict to the embedded instance.

Features:

 * random response is possible of big sizes
 * timeout can be randomized

See merge request nexedi/slapos!979

This fixes 157dd7ab.

It workarounds stack/resilient/pbsready.cfg.in directory:backup string
concatenation:

  backup = $${basedirectory:backup}/$${slap-parameter:namebase}

See merge request nexedi/slapos!981

This fixes:

  Installing jupyter.
  While:
    Installing jupyter.
    Base installation request: ...
    Getting distribution for 'argon2-cffi'.
  Error: Picked: argon2-cffi = 20.1.0

Addition of argon2-cffi in commit 7d1ea024
was a last-minute change to fix jupyter SR.

Accessing http with path starting with /HTTPS/ would result with 503 responses
from ATS itself.

Test is covering the problem and also asserting that fix does not damage https
access with path starting with /HTTP/

This defers the rendering of `instance-theia.cfg.in` to the instance
creation time instead of the software installation time, which will
allow buildout sections to be added based on the instance parameters.

See merge request !981

Edggetest monitoring got capability of region definition in each cluster.

In order to stabilise parameter serialisation the json-in-xml has been used.

Slave reference can be dangerous for buildout validity or file names.