The webkit2gtk3 package is not available on manylinux2014

[rmartin16]

Describe the bug

The Briefcase template defaults to building on manylinux2014 and using the webkit2gtk3 package for WebKit2 support for AppImage....but the webkit2gtk3 doesn't exist for CentOS 7.

Steps to reproduce

❯ docker run --rm -it quay.io/pypa/manylinux2014_x86_64 yum search webkit2gtk3
Loaded plugins: fastestmirror, ovl
Determining fastest mirrors
epel/x86_64/metalink                                                          |  28 kB  00:00:00     
 * base: atl.mirrors.clouvider.net
 * centos-sclo-rh: mirror.vacares.com
 * epel: atl.mirrors.knownhost.com
 * extras: nc-centos-mirror.iwebfusion.net
 * updates: us.mirrors.virtono.com
base                                                                          | 3.6 kB  00:00:00     
centos-sclo-rh                                                                | 3.0 kB  00:00:00     
epel                                                                          | 4.7 kB  00:00:00     
extras                                                                        | 2.9 kB  00:00:00     
updates                                                                       | 2.9 kB  00:00:00     
(1/8): base/7/x86_64/group_gz                                                 | 153 kB  00:00:00     
(2/8): epel/x86_64/group_gz                                                   |  99 kB  00:00:00     
(3/8): extras/7/x86_64/primary_db                                             | 249 kB  00:00:00     
(4/8): base/7/x86_64/primary_db                                               | 6.1 MB  00:00:00     
(5/8): epel/x86_64/primary_db                                                 | 7.0 MB  00:00:00     
(6/8): updates/7/x86_64/primary_db                                            |  21 MB  00:00:03     
(7/8): centos-sclo-rh/x86_64/primary_db                                       | 3.4 MB  00:00:10     
(8/8): epel/x86_64/updateinfo                                                 | 1.0 MB  00:00:00     
Warning: No matches found for: webkit2gtk3
No matches found

In contrast:

❯ docker run --rm -it quay.io/pypa/manylinux_2_28_x86_64 yum search webkit2gtk3
AlmaLinux 8 - BaseOS                                                  10 MB/s | 3.8 MB     00:00    
AlmaLinux 8 - AppStream                                              7.5 MB/s |  11 MB     00:01    
AlmaLinux 8 - Extras                                                  47 kB/s |  18 kB     00:00    
AlmaLinux 8 - PowerTools                                             7.1 MB/s | 2.9 MB     00:00    
================================= Name Exactly Matched: webkit2gtk3 =================================
webkit2gtk3.i686 : GTK Web content engine library
webkit2gtk3.x86_64 : GTK Web content engine library

Expected behavior

Ideally, out of the box support for building AppImages with WebKit2 support.

However, AppImage support is particularly flaky for reasons out of BeeWare's control....so, just removing the webkit2gtk3 package from the appimage configuration also seems appropriate.

Screenshots

No response

Environment

• Operating System: ubuntu 22.04
• Python version: 3.11.4
• Software versions:
  • Briefcase: 0.3.15.dev348+g0615d743

Logs

No response

Additional context

I think we got here when we stopped installing webkit2gtk3 by default when the template was still using ubuntu1804 but didn't notice when we switched to manylinux2014.

[freakboy3742]

Agreed this is a problem; it's also worth adding a documentation note about the problems using WebKit under AppImage.