reject TPA-RFC-15 (team#40363)

The rationale here is that we prefer to outsource the technical and
staff risks to outside, because TPA is already pretty loaded.

The problem, now, of course, is that we need to make a NEW RFC, but
one thing at a time.

For details, see tpa-team email with Message-ID:
CAAA5PKyJBWX82MYmXPX-Uq8+U00tO8DDFDA0yoGjYAOOX8qTVw@mail.gmail.com

policy.md

@@ -23,7 +23,6 @@ and add it to the above list.
 
 <!-- No policy is currently `proposed`. -->
 
- * [TPA-RFC-15: Email services](policy/tpa-rfc-15-email-services)
  * [TPA-RFC-26: LimeSurvey upgrade](policy/tpa-rfc-26-limesurvey-upgrade)
  * [TPA-RFC-29: Lektor SCSS Plugin](policy/tpa-rfc-29-lektor-scss-plugin)
  * [TPA-RFC-30: Changing how lego plugins are used](policy/tpa-rfc-30-change-lego-plugins)
@@ -46,7 +45,7 @@ and add it to the above list.
 
 ## Rejected
 
-No policy has been `rejected` so far.
+ * [TPA-RFC-15: Email services](policy/tpa-rfc-15-email-services)
 
 ## Obsolete
 

policy/tpa-rfc-15-email-services.md

@@ -1021,7 +1021,7 @@ the former.
 
 # Status
 
-This proposal is currently in the `proposed` state.
+This proposal is currently in the `rejected` state.
 
 # References