Cleanup this not used command

src/documents/management/commands/loaddata_stdin.py

@@ -1,22 +0,0 @@
-import sys
-
-from django.core.management.commands.loaddata import Command as LoadDataCommand
-
-
-# This class is used to migrate data between databases
-# That's difficult to test
-class Command(LoadDataCommand):  # pragma: no cover
-    """
-    Allow the loading of data from standard in.  Sourced originally from:
-    https://gist.github.com/bmispelon/ad5a2c333443b3a1d051 (MIT licensed)
-    """
-
-    def parse_name(self, fixture_name):
-        self.compression_formats["stdin"] = (lambda x, y: sys.stdin, None)
-        if fixture_name == "-":
-            return "-", "json", "stdin"
-
-    def find_fixtures(self, fixture_label):
-        if fixture_label == "-":
-            return [("-", None, "-")]
-        return super().find_fixtures(fixture_label)