feat(notif): issue notifications (#2242)

* feat(notif): issue notifications

* refactor: dedupe test notification strings

* fix: webhook key parsing

* fix(notif): skip send for admin who requested on behalf of another user

* fix(notif): send comment notifs to admins when other admins reply

* fix(notif): also send resolved notifs to admins, and reopened notifs to issue creator

* fix: don't send duplicate notifications

* fix(lang): tweak notification description strings

* fix(notif): tweak Slack notification styling

* fix(notif): tweak Pushbullet & Telegram notification styling

* docs: reformat webhooks page

* fix(notif): add missing issue_type & issue_status variables to LunaSea notif payloads

* fix: explicitly attach media & issue objects where applicable

* fix(notif): correctly notify both notifyUser and managers where applicable

* fix: update default webhook payload for new installs

* fix(notif): add missing comment_message to LunaSea notif payload

* refactor(sw): simplify notificationclick event listener logic

* fix(notif): add missing event description for MEDIA_AVAILABLE notifications

server/templates/email/media-request/html.pug

@@ -66,4 +66,4 @@ div(style='display: block; background-color: #111827; padding: 2.5rem 0;')
         td
           a(href=actionUrl style='display: block; margin: 1.5rem 3rem 0; text-decoration: none; font-size: 1.0em; line-height: 2.25em;')
             span(style='padding: 0.2rem; font-weight: 500; text-align: center; border-radius: 10px; background-color: rgb(99,102,241); color: #fff; display: block; border: 1px solid rgba(255,255,255,0.2);')
-              | Open in #{applicationTitle}
+              | View Media in #{applicationTitle}

server/templates/email/media-request/subject.pug

@@ -1 +1 @@
-!= `${requestType} - ${mediaName} [${applicationTitle}]`
+!= `${event} - ${mediaName} [${applicationTitle}]`