Put CSV import function under its own module

src/invidious/user/imports.cr

@@ -1,27 +1,33 @@
 require "csv"
 
-def parse_subscription_export_csv(csv_content : String)
-  rows = CSV.new(csv_content, headers: true)
-  subscriptions = Array(String).new
+struct Invidious::User
+  module Import
+    extend self
 
-  # Counter to limit the amount of imports.
-  # This is intended to prevent DoS.
-  row_counter = 0
+    # Parse a youtube CSV subscription file
+    def parse_subscription_export_csv(csv_content : String)
+      rows = CSV.new(csv_content, headers: true)
+      subscriptions = Array(String).new
 
-  rows.each do |row|
-    # Limit to 1200
-    row_counter += 1
-    break if row_counter > 1_200
+      # Counter to limit the amount of imports.
+      # This is intended to prevent DoS.
+      row_counter = 0
 
-    # Channel ID is the first column in the csv export we can't use the header
-    # name, because the header name is localized depending on the
-    # language the user has set on their account
-    channel_id = row[0].strip
+      rows.each do |row|
+        # Limit to 1200
+        row_counter += 1
+        break if row_counter > 1_200
 
-    next if channel_id.empty?
+        # Channel ID is the first column in the csv export we can't use the header
+        # name, because the header name is localized depending on the
+        # language the user has set on their account
+        channel_id = row[0].strip
 
-    subscriptions << channel_id
+        next if channel_id.empty?
+        subscriptions << channel_id
+      end
+
+      return subscriptions
+    end
   end
-
-  return subscriptions
 end