Rename mixin methods which are incorrectly labeled protected

[mikkonie]

Not sure why I have originally done this, but a lot of mixins have public methods prefixed with _protected_syntax(). This is incorrect and creates issues e.g. when we in fact want to have some protected or private methods which the actual mixin API methods need to call.

This also affects several testing classes so sadly it is a breaking change.

It's bothered me for a while and it seems a good time to get this over with in milestone v0.12.0, which will break a lot of things in any case.

[mikkonie]

List of renamed methods with current naming:

adminalerts.tests.test_models.AdminAlertMixin.make_alert()
appalerts.tests.test_models.AppAlertMixin.make_app_alert()
filesfolders.tests.test_models.FileMixin.make_file()
filesfolders.tests.test_models.FolderMixin.make_folder()
filesfolders.tests.test_models.HyperLinkMixin.make_hyperlink()
filesfolders.views.FilesfoldersTimelineMixin.add_item_modify_event()
projectroles.tests.test_commands.BatchUpdateRolesMixin.write_file()
projectroles.tests.test_models.ProjectMixin.make_project()
projectroles.tests.test_models.ProjectInviteMixin.make_invite()
projectroles.tests.test_models.AppSettingMixin.make_setting()
projectroles.tests.test_models.ProjectUserTagMixin.make_tag()
projectroles.tests.test_models.RemoteSiteMixin.make_site()
projectroles.tests.test_models.RemoteProjectMixin.make_remote_project()
projectroles.tests.test_models.RemoteTargetMixin.set_up_as_target()
projectroles.tests.test_models.RemoteTargetMixin.set_up_as_target()
projectroles.tests.test_models.SODARUserMixin
projectroles.tests.test_models.SODARUserMixin.make_sodar_user()
projectroles.tests.test_models.RoleAssignmentMixin.make_assignment()
projectroles.tests.test_ui.LiveUserMixin.make_user()
projectroles.tests.test_views_api.SODARAPIViewTestMixin.get_basic_auth_header()
projectroles.views_api.ProjectInviteAPIMixin.validate()
sodarcache.tests.test_models.JsonCacheItemMixin.make_item()
timeline.tests.test_models.ProjectEventMixin.make_event()
timeline.tests.test_models.ProjectEventObjectRefMixin.make_object_ref()
timeline.tests.test_models.ProjectEventStatusMixin.make_event_status()

[mikkonie]

Done.