Reduce the test installation time.

It would be nice to include the configurator too.

Fix the bt5 dependencies.

Change tests so that they all use the configurator to install the bt5.

officejs_upgrader: use the same configuration than the configurator

/reviewed-on !5

/reviewed-on !3

This assuers, that distribution will be available in shacache.

Remove charset format for content type
Add hash when necessary

/reviewed-on !1

Redirect URL was modified at nexedi/erp5@e79dcdaf

They are provided by generic bt5