feat: add legal page with configuration options (#724)

* Addconfig entries for legal notice

* Add legal route handling to middleware

* Make legal notice public

* Add legal category to config sidebar

* Add legal notice page

* Add German translations for legal notice and configuration options

* Replace legal page with separate imprint and privacy pages

* Update middleware

* Add footer component

* Update legal text descriptions to indicate Markdown support again

* Refactor footer layout

* Add zIndex to footer component

* improve mobile layout

* run formatter

---------

Co-authored-by: Elias Schneider <login@eliasschneider.com>

backend/prisma/seed/config.seed.ts

@@ -349,6 +349,33 @@ const configVariables: ConfigVariables = {
       defaultValue: "",
       obscured: true,
     },
+  },
+  legal: {
+    enabled: {
+      type: "boolean",
+      defaultValue: "false",
+      secret: false,
+    },
+    imprintText: {
+      type: "text",
+      defaultValue: "",
+      secret: false,
+    },
+    imprintUrl: {
+      type: "string",
+      defaultValue: "",
+      secret: false,
+    },
+    privacyPolicyText: {
+      type: "text",
+      defaultValue: "",
+      secret: false,
+    },
+    privacyPolicyUrl: {
+      type: "string",
+      defaultValue: "",
+      secret: false,
+    },
   }
 };