(cherry picked from commit 2c9dfd0b732d24d5fa3adf99fd337ac45d8fec66)

(cherry picked from commit b2b7a123ebed4d962b08b6a1fd8565d5d66195b3)

Noticed by Benjamin.
(cherry picked from commit e51770f440db737f4904a24cb4d3180d422b0702)

Scalability: test

scalability: fix md5

scalability: Fix command-line launcher binary path

scalability: fix testsuite name

scalability: test

Update code

Simplifies editing the software release by removing the need to edit
instance-erp5-cluster.cf.in each time.
Applied to kumofs, cloudooo, mariadb and zodb.
Partially applied to frontend, as it is more complex.
Not applied to zope, as it is even more complex - but also topical to this
software release.
Also, change default timezone to UTC, to be neutral.
Also, reformat section extension.

Also, replace cloudooo-json by exposing its internals directly.

vincent: Minor fixes. Move branch switch to a separate commit.

Loosened checks are considered safe enough, and the speedup on many-GB
FileStorage files is significant.