[FIX] Calculate date interval using super user time zone

When you set the date of a cron the July 1st at midnight, if the user
time zone has a positive offset, then the converted UTC date is the
June 30th and adding 1 month will end up on July 30th translating to
July 31th instead of September 1st.

To solve this issue we use the super user time zone for the date
calculation.
[FIX] web_kanban : resequence column and content by drag and dropping
[FIX] yaml tests: Set on_change keys not in view logger as debug instead of warning

This is related to commit d31faceb67fd87acaca00365dcfc28925b08a37f
(This is to avoid the runbot being yellow if on_change methods have extra keys in the returned value, this is not wrong, the web client will simply ignore them).
[FIX] web: image fields re-render on next/previous

By default, on binary images read, the server returns the binary size
This is possible that two images have the exact same size
Therefore we trigger the change in case the image value hasn't changed
So the image is re-rendered correctly
[MERGE] forward port of branch 7.0 up to 3632949