Add authorisation process for sign ups and allow access to EventDetail for basic users (#399)

* CHANGE: First pass at opening up RIGS #233

Whilst it makes it something of a misnomer, the intent is to make the 'view_event' perm a permission to view event details like client/price. I don't see the point in giving everyone 'view_event' and adding a new 'view_event_detail'...Open to arguments the other way.

* CHANGE: New user signups now require admin approval

Given that I intend to reveal much more data to new users this seems necessary...

* CHORE: Fix CI

* FIX: Legacy Profiles are now auto-approved correctly

* Add testing of approval mechanism

This fixes the other functional tests failing because the user cannot login without being approved.

* Superusers bypass approval check

This should fix the remainder of the tests

* Prevent unapproved users logging in through embeds

Test suite doing its job...!

* FIX: Require login on events and event embeds again

Little too far to the open side there Arona... Whooooooops!

* FIX: Use has_oembed decorator for events

* FIX: Re-prevent basic seeing reversion

This is to prevent financials/client data leaking when changed. Hopefully can show them a filtered version in future.

* FIX: Remove mitigation for #264

Someone quietly fixed it, it appears

* FEAT: Add admin email notif when an account is activated and awaiting approval

No async or time-since shenanigans yet!

* FIX: Whoops, undo accidental whitespace change

* FEAT: Add a fifteen min cooldown between emails to admins

Probably not the right way to go about it...but it does work!

TODO: How to handle cooldown-emailing shared mailbox addresses?

* FIX: Remove event modal history deadlink for basic users

Also removes some links on the RIGS homepage that will deadlink for them

* FIX: Wrong perms syntax for history pages

* CHORE: Squash migrations

* FIX: Use a setting for cooldown

* FIX: Minor code improvements

RIGS/migrations/0036_profile_is_approved.py

@@ -0,0 +1,23 @@
+# Generated by Django 2.0.13 on 2020-01-10 14:52
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('RIGS', '0035_auto_20191124_1319'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='profile',
+            name='is_approved',
+            field=models.BooleanField(default=False),
+        ),
+        migrations.AddField(
+            model_name='profile',
+            name='last_emailed',
+            field=models.DateTimeField(blank=True, null=True),
+        ),
+    ]

RIGS/migrations/0037_approve_legacy.py

@@ -0,0 +1,19 @@
+# Generated by Django 2.0.13 on 2020-01-11 18:29
+# This migration ensures that legacy Profiles from before approvals were implemented are automatically approved 
+from django.db import migrations
+
+def approve_legacy(apps, schema_editor):
+    Profile = apps.get_model('RIGS', 'Profile')
+    for person in Profile.objects.all():
+        person.is_approved = True
+        person.save()
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('RIGS', '0036_profile_is_approved'),
+    ]
+
+    operations = [
+        migrations.RunPython(approve_legacy)
+    ]