Update globals.py and support for 'nested' apps

[ColemanDunn]

DRF 3.14.0 support

see https://stackoverflow.com/questions/73823833/attributeerror-module-rest-framework-serializers-has-no-attribute-nullboolea for more info

[ColemanDunn]

For the second commit: If the project structure as shown in the DRF quickstart guide is followed, in which your app is 'nested' within your project, then your app_config.name will be in the format of project_name.app_name which is incompatible with module.split('.')[0] == app_config.name. I therefore switched it to if module.startswith(app_config.name) to follow the same principle of checking the first part of the name while also being compatible with this kind of project structure.