Don't duplicate code for Apple menu creation.

Have just one copy of the code, instead of two. Eliminate differences
between the two versions. As a result, applications now properly have
preferences and about items even if window-less.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/branches/WX_3_0_BRANCH@75224 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
Fix i18n-unfriendly About menu code in wxOSX.

The code didn't follow the golden rule of localization and broke
user-visible string into separately translated substrings.  Replace with
the same _("About %s") string already used in wxAboutDialog.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/branches/WX_3_0_BRANCH@75225 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
Add wxMenuBar::OSXGetAppleMenu().

Native OS X apps sometimes have certain app-wide comments in the
Apple/app menu ("Check for Updates" is a typical example).  Make it
possible to write well-behaved OS X apps by exposing this menu to user
code.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/branches/WX_3_0_BRANCH@75226 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
Put Services submenu into the Apple menu on OS X.

Native applications have a Services submenu in the apple menu.  wx
applications didn't until now.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/branches/WX_3_0_BRANCH@75227 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
Fix Czech translation of "About %s".

It is used for the app name, translate it in the commonly used way
("About application %s").

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/branches/WX_3_0_BRANCH@75228 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775