[CORL-645] Add Slack support for v5 (#2713)

* Create preliminary schema for setting Slack channels

CORL-645

* Implement preliminary slack notification using tenant slack channels

CORL-645

* Very preliminarily get data loading with FieldArray's for slack channels

CORL-645

* Update settings input on schema to allow saving Slack settings to tenant

CORL-645

* Filter off UNMODERATED queue events from slack channels

We don't send these to slack through our filters, we only care
about pending, reported, and featured

CORL-645

* Include a moderation link in comments pushed to Slack

CORL-645

* Hook up proper callback functions for adding/removing slack channels

CORL-645

* Add missing translation for Slack navigation item

CORL-645

* Update snapshots for preliminary Slack configuration changes

CORL-645

* Add some FormField wrappers around slack config elements

Makes the UI appear a little nicer

CORL-645

* Set up slack config to only provide one slack channel

We need to do this until we can get ArrayField's working
in final-form.

CORL-645

* Disable the other trigger checkboxes when "All Comments" is checked

CORL-645

* Clean up the formatting of Slack messages

CORL-645

* Add error handling around sending comments to Slack

CORL-645

* Add links to external Slack setup documentation

CORL-645

* Replace form state with wrapped field element

CORL-645

* Clean up fetch request sending Slack notifications

CORL-645

* Prefer global string replacement over RegEx

CORL-645

* Use URL class to construct comment URL's

CORL-645

* Require slack configuration in schema

CORL-645

* Initialize Slack in fixtures

Also fix up a flaky test that wasn't waiting
on form submission and on-change events.

CORL-645

* Preliminarily fix up styles to match other config pages

CORL-645

* Create placeholder add/remove buttons

* Convert SlackConfigContainer to FunctionalComponent

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* Add name field to slack channels

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* Disable inner fields on Slack channel when not enabled

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* Improve the delete channel button

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* Use pureMerge to extract slack channel settings

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* Do a bit of cleanup on the add channel button

CORL-645

src/core/server/models/settings.ts

@@ -137,6 +137,7 @@ export type Settings = GlobalModerationSettings &
     | "communityGuidelines"
     | "stories"
     | "createdAt"
+    | "slack"
   > & {
     /**
      * auth is the set of configured authentication integrations.

src/core/server/models/tenant/tenant.ts

@@ -190,6 +190,9 @@ export async function createTenant(
       downloadComments: false,
     },
     createdAt: now,
+    slack: {
+      channels: [],
+    },
   };
 
   // Create the new Tenant by merging it together with the defaults.