Availability rules position get mixed with gCal rules and don't respect the position

[Valentina R]

Ordering the rules has an effect with priority, “rules further down the table will override those at the top”.

If I drag my rules in the table to change the order, for example dragging the regular rules to the very bottom, they do not stay there. When Gcal syncs new rules everything seems to just get randomized. This can cause problems with rules not having the right priority.

Reported here: https://bookingwp.com/forums/topic/feature-request-please-separate-out-the-availability-rules/

The same person also suggested this, and perhaps it might fix this problem.

[Željan Topić]

Duplicate of #506.