Convert additional templates to Jinja (#8444)

This converts a few more of our inline HTML templates to Jinja. This is somewhat part of #7280 and should make it a bit easier to customize these in the future.

synapse/config/consent_config.py

@@ -89,6 +89,8 @@ class ConsentConfig(Config):
 
     def read_config(self, config, **kwargs):
         consent_config = config.get("user_consent")
+        self.terms_template = self.read_templates(["terms.html"], autoescape=True)[0]
+
         if consent_config is None:
             return
         self.user_consent_version = str(consent_config["version"])