Add ActivityPub actor representing the entire server (#11321)

* Add support for an instance actor

* Skip username validation for local Application accounts

* Add migration script to create instance actor

* Make Codeclimate happy

* Switch to id -99 for instance actor

* Remove unused `icon` and `image` attributes from instance actor

* Use if/elsif/else instead of return + ternary operator

* Add instance actor to fresh installs

* Use instance actor as instance representative

Use instance actor for forwarding reports, relay operations, and spam
auto-reporting.

* Seed database in test environment

* Fix single-user mode

* Fix tests

* Fix specs to accomodate for an extra `Account`

* Auto-reject follows on instance actor

Following an instance actor might make sense, but we are not handling that
right now, so auto-reject.

* Fix webfinger lookup and serialization for instance actor

* Rename instance actor

* Make it clear in the HTML view that the instance actor should not be blocked

* Raise cache time for instance actor as there's no dynamic content

* Re-use /about/more with a flash message for instance actor profile

1 files changed, 4 insertions, 0 deletions

diff --git a/app/javascript/styles/mastodon/containers.scss b/app/javascript/styles/mastodon/containers.scss
index 3564bf07b..2b6794ee2 100644
--- a/app/javascript/styles/mastodon/containers.scss
+++ b/app/javascript/styles/mastodon/containers.scss
@@ -145,6 +145,10 @@
     min-height: 100%;
   }
 
+  .flash-message {
+    margin-bottom: 10px;
+  }
+
   @media screen and (max-width: 738px) {
     grid-template-columns: minmax(0, 50%) minmax(0, 50%);