feat(gui-client): polish Linux bundling (#9181)

Tauri's `deb` and `rpm` bundler have support for configuring maintainer
scripts. We can therefore just use those instead of tearing apart the
`deb` file that it creates and rebuilding it ourselves.

Our `rpm` packaging is currently completely broken as well. I couldn't
get it to work on CentOS 9 at all due to missing dependencies, likely
introduced by our move to Tauri v2. It installs fine on CentOS 10
though, assuming that the user has the EPEL repository installed which
provides the WebView dependency. I extended the docs to reflect this.

Hence, with this PR, we drop support for CentOS 9 and now require CentOS
10. This allows us to remove a lot of cruft from our bundling process
and instead entirely rely on the Tauri provided bundler.

Lastly, for consistency with other platforms, the name of the
application in places like app drawers has been changed from "Firezone
Client" to just "Firezone".

---------

Signed-off-by: Thomas Eizinger <thomas@eizinger.io>

.github/workflows/_tauri.yml

@@ -116,7 +116,7 @@ jobs:
       - name: Upload deb / msi package
         uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4.6.2
         with:
-          name: ${{ env.ARTIFACT_DST }}-pkg
+          name: ${{ env.ARTIFACT_DST }}-${{ matrix.pkg-extension }}
           path: ${{ env.ARTIFACT_SRC }}.${{ matrix.pkg-extension }}
           if-no-files-found: error
       - name: Upload rpm package