When editing a dive site in the 'Dive sites' view, add a context menu
entry to allow mergeing of the displayed dive site into the dive site
seleted in the 'Near dive sites' list.
This merge has the opposite direction of the existing 'Merge into
current site' function, which can simplify the workflow when maintaining
a large number of dive sites, as the facilities to sort dive sites in
the 'Dive sites' view does not have a way to sort by location or
proximity.
Signed-off-by: Michael Keller <github@ike.ch>
2aa13ea9d7