The container of modal and popup components was always set to
"#content-vue" to ensure that they will be properly shown in normal and
fullscreen mode in the main Talk UI. However, when Talk is embedded in
the Files app, the share page or the video verification there is no such
element, so the container for the components could not be set and thus
they were not shown.

To solve this now the selector for the main container element is got
from the store instead of being hardcoded, and the different UI modes
set the appropriate value when initialized (or leave it undefined to use
the default one, typically the body element, when a specific element is
not needed).

Note that this change applies too to some components that, right now,
are only shown in the main Talk UI, but it was done for consistency and
to make them "future-proof".

Signed-off-by: Daniel Calviño Sánchez <[email protected]>

Using the default container causes the action menus in the Talk tab to
be repositioned at wrong places when the menus are shown and the file
list is scrolled. To address this (although it does not fully fix the
issue, there are still some strange behaviours) the main container for
Talk components used when Talk is embedded in the Files app is Talk tab.
Besides that, both the container and the boundaries element of the
actions are set to the Talk tab.

Despite setting the main container this change does not affect other
components (like the room selector) or slightly improves their behaviour
(like the author avatar menu, which no longer appears outside the tab
when scrolling).

Signed-off-by: Daniel Calviño Sánchez <[email protected]>

Signed-off-by: Joas Schilling <[email protected]>