feat: delete unconfirmed users

Author: pajgo

doc/rfcs/inactive_users_cleanup.md

@@ -0,0 +1,17 @@
+# Inactive user cleanup
+When user registration process finishes and users not passing "activation", corresponding DB record stays for ttl.
+But all metadata/alias/email records stay forever.
+
+#### Possible variant
+- Create additional set with id's of inactive users (`users-activate`).
+  * Change activation process: remove successfully activated user id from `users-activate`.
+  * Change registration process: insert inactive user id into `users-activate`.
+- Add repeating task with interval `config.incativeCleanupInterval`.
+  * Sets `dlock` for cleanup operation
+  * Gets list from `user-activate`
+  * Delete all corresponding data from DB for this user id's:
+    all keys `{id}!metadata!{audience}`, and keys from hashes: `USERS_USERNAME_TO_ID`,`USERS_ALIAS_TO_ID`.
+  
+    _NOTE_:
+    User already can be assigned to some organization. So we'll check organisation members key (`redisKey(organizationId, ORGANIZATIONS_MEMBERS)`), organisation member key (`redisKey(organizationId, ORGANIZATIONS_MEMBERS, member.email)`) and redisKey(member.email, USERS_ORGANIZATIONS);
+