This commit adds a new service "overlay" that will be used as a base
for other service which displays a component on foreground like
"popover" or "dialog". The services "popover", "dialog" and "effect"
already uses this new service to have a common container.
The "overlay" service also fix a stacking context issue that could
happen when a popover opened a dialog and this dialog then opened
another popover thanks to the common container.
task id: 3233266
closesodoo/odoo#115308
Related: odoo/enterprise#38786
Signed-off-by: Bruno Boi (boi) <boi@odoo.com>
Michael (mcm)
8da2b52333