[Enhancement] Record and display errors related to downloading (#610)

* Added last_error to media item table

* Error messages are now persisted to the last_error field

* Minor layout updates

* Added help tooltip to source content view

* Added error information to homepage tables

* Remove unneeded index

* Added docs to tooltip component

lib/pinchflat/utils/string_utils.ex

@@ -35,4 +35,13 @@ defmodule Pinchflat.Utils.StringUtils do
   def double_brace(string) do
     "{{ #{string} }}"
   end
+
+  @doc """
+  Wraps a string in quotes if it's not already a string. Useful for working with
+  error messages whose types can vary.
+
+  Returns binary()
+  """
+  def wrap_string(message) when is_binary(message), do: message
+  def wrap_string(message), do: "#{inspect(message)}"
 end