switch blockchain include directives to use hive

This will enable the hive_post directive for content that is found on the blockchain. Affected pages:

• https://developers.hive.io/tutorials-recipes/how-to-serialize-and-sign-using-js.html
• https://developers.hive.io/tutorials-recipes/mira-performance-tuning.html
• https://developers.hive.io/tutorials-recipes/using-multisignatire-accounts.html