Change references to ofirehose.com

[ghost]

Due https://ofirehose.com is down for a while and is promoting a kind of centralized service we should change the default option and suggestions from https://ofirehose.com to something like https://ofirehose.yourdomain.com, the documentation must be updated to redirect to the ofirehose repo and invite to install an instance.

also in my instance and like others, we live without ofirehose, so we should remove if from sample configuration in order to facilitate initial understanding because currently not exist stable public ofirehose services.

Related: #1698

[prologic]

I see... This helps a lot! Thanks!