manage: properly fallback to config.default

refs #16083
Add callable for wsgi

refs #16083
manage: add a gather command

refs #16119
remove import_siteinfo script

Not needed as it is now a manage command (gather)

refs #16119
Merge branch 'bug/16119' into develop
Merge branch 'bug/16083' into develop
Form should be auto-filled on page load now.

refs #16071
Fixed scoping issue and added delete UX fix.

Previously, when an object was deleted, the next option was not
auto-populated into the old fields. This has since been corrected.

refs #16071
Fixed issue with updating new models.

Previously, we were posting to /<category>/undefined/add when trying update
new models. This was fixed so we not post correctly to /<category>/add.

refs #16071