We have a fallback string that gets searched for in the KCM, but that
fallback itself should not have a fallback, or else we always use that
second fallback and the window gets positioned incorrectly the first
time it's opened. So let's replace the second fallback with -1.

BUG: 432661
FIXED-IN: 5.79
(cherry picked from commit 97accd14d732f3eda1c25bb58290cb9311040798)

 * Doxygen sections instead of markdown list items and HTML headers
 * More descriptive section titles
 * HTML Definition list instead of a wide HTML table for compiler options
 * HTML Definition list instead of a markdown item list for data types
 * Syntax highlighting for examples

In case of conflict in i18n, keep the version of the branch "ours"
To resolve a particular conflict, "git checkout --ours path/to/file.desktop"

This commit refactors the code a bit to define the window geometry
strings in one place and uses a common method to read and write them.

This makes future changes much less fragile and fixes a pre-existing bug
that had gone un-noticed which caused window positions to not be saved
on a per-resolution basis in addition to a per-display-arrangement
basis. Old strings are used if available to that people don't lose their
saved position data the first time they upgrade to KF 5.79.

The maximization string was being saved to the config file including
the connected screens, but the code to read it was not, and was also
looking for the old incorrect format. This could have resulted in old
config values being used forever, and the window always being opened
in a maximized state.

BUG: 430521
FIXED-IN: 5.79

Frameworks will be Frameworks 6 at some point and there is no good reason to have the major version in the variable name.

Given this is purely internal we can to this now, making it a bit more future-proof

GIT_SILENT

NO_CHANGELOG

KDEWIN_LIBRARIES is never defined