Add API to add custom `infe` items

[farindk]

Some applications might want to safe non-standardized data into the HEIF file. To enable this use case, there should be an API function to write (and read) custom data items.

a. Adding an optional item_name b. Specifying the construction method (store in mdat or idat) c. An option to associate the item with 0, 1, or multiple other infe items. d. For items of type ‘uri ‘, specify the item_uri_type