🚚(backend) rename Impress to Meet

I have updated all references of "Impress" to "Meet".
Migrations were manually updated and not regenerated. Never-mind,
they all will be squashed before the first release.

I have also searched for reference to "Magnify", and replaced them
by "Meet".

While updating the backend sources, I have also fixed other parts of
the project, namely:
- Compose file
- Github documentation and CI
- Makefile commands

src/backend/core/tests/rooms/test_api_rooms_create.py

@@ -1,5 +1,5 @@
 """
-Test rooms API endpoints in the impress core app: create.
+Test rooms API endpoints in the Meet core app: create.
 """
 import pytest
 from rest_framework.test import APIClient

src/backend/core/tests/rooms/test_api_rooms_delete.py

@@ -1,5 +1,5 @@
 """
-Test rooms API endpoints in the impress core app: delete.
+Test rooms API endpoints in the Meet core app: delete.
 """
 import pytest
 from rest_framework.test import APIClient

src/backend/core/tests/rooms/test_api_rooms_list.py

@@ -1,5 +1,5 @@
 """
-Test rooms API endpoints in the impress core app: list.
+Test rooms API endpoints in the Meet core app: list.
 """
 from unittest import mock
 

src/backend/core/tests/rooms/test_api_rooms_retrieve.py

@@ -1,5 +1,5 @@
 """
-Test rooms API endpoints in the impress core app: retrieve.
+Test rooms API endpoints in the Meet core app: retrieve.
 """
 import random
 from unittest import mock

src/backend/core/tests/rooms/test_api_rooms_update.py

@@ -1,5 +1,5 @@
 """
-Test rooms API endpoints in the impress core app: update.
+Test rooms API endpoints in the Meet core app: update.
 """
 import random