Move TimeSpanConverter with another Converters

Follow indications :
https://github.com/iv-org/invidious/pull/2915#discussion_r811373953

src/invidious/config.cr

@@ -59,7 +59,7 @@ class Config
   # Number of threads to use for crawling videos from channels (for updating subscriptions)
   property channel_threads : Int32 = 1
   # Time between two jobs for crawling videos from channels
-  @[YAML::Field(converter: TimeSpanConverter)]
+  @[YAML::Field(converter: Preferences::TimeSpanConverter)]
   property channel_refresh_interval : Time::Span = 30.minutes
   # Number of threads to use for updating feeds
   property feed_threads : Int32 = 1

src/invidious/helpers/utils.cr

@@ -18,20 +18,6 @@ def elapsed_text(elapsed)
   "#{(millis * 1000).round(2)}µs"
 end
 
-module TimeSpanConverter
-  def self.to_yaml(value : Time::Span, yaml : YAML::Nodes::Builder)
-    return yaml.scalar recode_length_seconds(value.total_seconds.to_i32)
-  end
-
-  def self.from_yaml(ctx : YAML::ParseContext, node : YAML::Nodes::Node) : Time::Span
-    if node.is_a?(YAML::Nodes::Scalar)
-      return decode_time_span(node.value)
-    else
-      node.raise "Expected scalar, not #{node.class}"
-    end
-  end
-end
-
 def decode_time_span(string : String) : Time::Span
   time_span = string.gsub(/[^0-9:]/, "")
   return Time::Span.new(seconds: 0) if time_span.empty?

src/invidious/user/preferences.cr

@@ -256,4 +256,18 @@ struct Preferences
       cookies
     end
   end
-end
+
+  module TimeSpanConverter
+    def self.to_yaml(value : Time::Span, yaml : YAML::Nodes::Builder)
+      return yaml.scalar recode_length_seconds(value.total_seconds.to_i32)
+    end
+
+    def self.from_yaml(ctx : YAML::ParseContext, node : YAML::Nodes::Node) : Time::Span
+      if node.is_a?(YAML::Nodes::Scalar)
+        return decode_time_span(node.value)
+      else
+        node.raise "Expected scalar, not #{node.class}"
+      end
+    end
+  end
+end