PLT-6965 jira integration (plus plugin scaffolding) (#6918)

* plugin scaffolding / jira integration

* add vendored testify packages

* webhook fix

* don't change i18n ids

* support configuration watching

* add basic jira plugin configuration to admin console

* fix eslint errors

* fix another eslint warning

* polish

* undo unintentional config.json commit >:(

* test fix

* add jira plugin diagnostics, remove dm support, add bot tag, generate web-safe secrets

* rebase, implement requested changes

* requested changes

* remove tests and minimize makefile change

* add missing license headers

* add missing comma

* remove bad line from Makefile

webapp/sass/routes/_admin-console.scss

@@ -305,6 +305,10 @@
     .status-icon-error {
         color: #ea6262;
     }
+    
+    .suggestion--selected {
+        background-color: #e2e2e2;
+    }
 }
 
 .brand-img {