feat: enable enterprise users to specify a custom logo (#5566)

* feat: enable enterprise users to specify a custom logo

This adds a field in deployment settings that allows users to specify
the URL to a custom logo that will display in the dashboard.

This also groups service banner into a new appearance settings page.
It adds a Fieldset component to allow for modular fields moving forward.

* Fix tests

site/src/testHelpers/entities.ts

@@ -1097,3 +1097,10 @@ export const MockPermissions: Permissions = {
   viewAuditLog: true,
   viewDeploymentConfig: true,
 }
+
+export const MockAppearance: TypesGen.AppearanceConfig = {
+  logo_url: "",
+  service_banner: {
+    enabled: false,
+  },
+}

site/src/testHelpers/handlers.ts

@@ -282,4 +282,8 @@ export const handlers = [
   rest.get("/api/v2/workspace-quota/:userId", (req, res, ctx) => {
     return res(ctx.status(200), ctx.json(MockWorkspaceQuota))
   }),
+
+  rest.get("/api/v2/appearance", (req, res, ctx) => {
+    return res(ctx.status(200), ctx.json(M.MockAppearance))
+  }),
 ]