Various errors from the production

[Xpirix]

The following errors raised from production should be handled:

• [x] TemplateDoesNotExist at /planet/
• [x] Object could not be found in database for SearchResult ''
• [x] FileNotFoundError at /api/v1/resources/
• [x] OSError
• [x] FieldError /wavefronts/
• [x] IntegrityError /plugins/{package_name}/version/{version}/download/
• [x] RequestDataTooBig /plugins/RPC2/
• [x] beat: Connection error: ConnectionRefusedError(111, 'Connection refused'). This occurs when the application starts.