Rename control plane selector to "service provider zone"

src/servala/core/models/service.py

@@ -90,6 +90,9 @@ def validate_api_credentials(value):
 
 
 class ControlPlane(models.Model):
+    """
+    Note: ControlPlanes are called "Service Provider Zone" in the user-facing frontend.
+    """
     name = models.CharField(max_length=100, verbose_name=_("Name"))
     description = models.TextField(blank=True, verbose_name=_("Description"))
     # Either contains the fields "certificate_authority_data", "server" and "token", or is empty

src/servala/frontend/forms/service.py

@@ -1,4 +1,5 @@
 from django import forms
+from django.utils.translation import gettext_lazy as _
 
 from servala.core.models import CloudProvider, ControlPlane, ServiceCategory
 
@@ -23,7 +24,9 @@ class ServiceFilterForm(forms.Form):
 
 
 class ControlPlaneSelectForm(forms.Form):
-    control_plane = forms.ModelChoiceField(queryset=ControlPlane.objects.none())
+    control_plane = forms.ModelChoiceField(
+        queryset=ControlPlane.objects.none(), label=_("Service Provider Zone")
+    )
 
     def __init__(self, *args, planes=None, **kwargs):
         super().__init__(*args, **kwargs)