Move example app to test app

[nickmoreton]

This move the example app to the test app

Issue: #160

• Testing
  • CI passes
  • If necessary, tests are added for new or fixed behaviour
  • These changes do not reduce test coverage
• Documentation.
  • This PR adds or updates documentation
  • Documentation changes are not necessary because:

[codecov-commenter]

Codecov Report

Merging #163 (f12d67c) into main (8b1e5ff) will increase coverage by 0.92%.
The diff coverage is 92.30%.

@@            Coverage Diff             @@
##             main     #163      +/-   ##
==========================================
+ Coverage   64.56%   65.48%   +0.92%     
==========================================
  Files          28       29       +1     
  Lines        1253     1298      +45     
  Branches      203      206       +3     
==========================================
+ Hits          809      850      +41     
- Misses        398      401       +3     
- Partials       46       47       +1     

Impacted Files	Coverage Δ
wagtail_wordpress_import/test/models.py	97.61% <90.00%> (ø)
wagtail_wordpress_import/test/settings.py	100.00% <100.00%> (ø)
...wordpress_import/management/commands/import_xml.py	84.84% <0.00%> (-9.10%)	⬇️

Help us with your feedback. Take ten seconds to tell us how you rate us. Have a feature suggestion? Share it here.