Fix issue where hardfork_hive_operation was too long to display in frontend

Implementation in FE: http://hive-staging.pl.syncad.com:5000/account/small.minion

My proposition is to use hafbe_backend.operation_body_filter that returns adjusted json body for operations that are listed in hafbe_endpoints.get_filtered_operations(). This way after adjusting the operation list in get_filtered_operations we can control which operation bodies are displayed in full in FE.

The view of the 'filtered' operation whole body is still work in progress and its not available on the FE yet, hafbe_endpoints.get_operation will be used to display the previously filtered body on the user's command