FEATURE: Add more columns to outbound EmailLog (#13449)

This adds the following columns to EmailLog:

* cc_addresses
* cc_user_ids
* topic_id
* raw

This is to bring the EmailLog table closer in parity to
IncomingEmail so it can be better utilized for Group SMTP
and IMAP mailing.

The raw column contains the full content of the outbound email,
but _only_ if the new hidden site setting
enable_raw_outbound_email_logging is enabled. Most sites do not
need it, and it's mostly required for IMAP and SMTP sending.

In the next pull request, there will be a migration to backfill
topic_id on the EmailLog table, at which point we can remove the
topic fallback method on EmailLog.

spec/models/email_log_spec.rb

@@ -110,4 +110,32 @@ describe EmailLog do
       expect(EmailLog.find(email_log.id).bounce_key).to eq(hex)
     end
   end
+
+  describe "cc addresses handling" do
+    let!(:email_log) { Fabricate(:email_log, user: user) }
+
+    describe "#cc_addresses_split" do
+      it "returns empty array if there are no cc addresses" do
+        expect(email_log.cc_addresses_split).to eq([])
+      end
+
+      it "returns array of cc addresses if there are any" do
+        email_log.update(cc_addresses: "test@test.com;test@test2.com")
+        expect(email_log.cc_addresses_split).to eq(["test@test.com", "test@test2.com"])
+      end
+    end
+
+    describe "#cc_users" do
+      it "returns empty array if there are no cc users" do
+        expect(email_log.cc_users).to eq([])
+      end
+
+      it "returns array of users if cc_user_ids is present" do
+        cc_user = Fabricate(:user, email: "test@test.com")
+        cc_user2 = Fabricate(:user, email: "test@test2.com")
+        email_log.update(cc_addresses: "test@test.com;test@test2.com", cc_user_ids: [cc_user.id, cc_user2.id])
+        expect(email_log.cc_users).to match_array([cc_user, cc_user2])
+      end
+    end
+  end
 end