desktop: rename to foot{,client,-server}.desktop

That is, skip the reverse DNS naming scheme suggested by the .desktop
specification, and directly match our app-ids ("foot", and
"footclient").

This simplifies .desktop -> window instance mapping, allowing DEs to
match the filenames directly, without having to look at the
StartupWMClass key in the .desktop files.

These are the original names of the .desktop files. There were
renamed (to use the reverse DNS syntax) to please the flathub people,
who *required* this scheme to accept the foot package.

But, since:

* We don't package foot ourselves
* We don't go out of our way to support non-distro packaging schemes
* Flathub still hasn't merged the foot PR (it's now 2 years old)
* There are no know issues in any known DE that prevents a non-reverse
  DNS .desktop filename from working
* There are plenty of other applications that doesn't use reverse DNS
  names (a very clear majority, in my case)

Let's just revert back to the simpler naming scheme.

Closes #1607

CHANGELOG.md

@@ -78,8 +78,12 @@
 * Sixel background color (when `P2=0|2`) is now set to the **sixel**
   color palette entry #0, instead of using the current ANSI background
   color. This is what a real VT340 does.
+* The `.desktop` files no longer use the reverse DNS naming scheme,
+  and their names now match the default app-ids used by foot (`foot`
+  and `footclient`) ([#1607][1607]).
 
 [1822]: https://codeberg.org/dnkl/foot/issues/1822
+[1607]: https://codeberg.org/dnkl/foot/issues/1607
 
 
 ### Deprecated

meson.build

@@ -317,7 +317,7 @@ executable(
   install: true)
 
 install_data(
-  'org.codeberg.dnkl.foot.desktop', 'org.codeberg.dnkl.foot-server.desktop', 'org.codeberg.dnkl.footclient.desktop',
+  'foot.desktop', 'foot-server.desktop', 'footclient.desktop',
   install_dir: join_paths(get_option('datadir'), 'applications'))
 
 systemd = dependency('systemd', required: false)