sw content controls, date: show a date picker on click

- add a new SwContentControl::GetDateString() that knows how to produce
a formatted date, taking the language and the date format into account

- add a new SwDateContentControlButton that knows how to open popup a
calendar on click and that puts the selected date into
SwContentControl::m_oSelectedDate

- extend SwWrtShell::GotoContentControl() to consume that selected date
& update the document text accordingly

- in case SwSelPaintRects::HighlightContentControl() notices a date
content control, create an instance of this newly introduced
SwDateContentControlButton

(cherry picked from commit ce5d609da9d20b3c91f6f8eb4ee88451cbd55a9d)

Change-Id: Ia2cb0fa3aefbf543b8dc2e96bcebb41408eb12c3
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/135116
Tested-by: Miklos Vajna <vmiklos@collabora.com>
Reviewed-by: Miklos Vajna <vmiklos@collabora.com>

0 files changed, 0 insertions, 0 deletions