core: Add http2errno
core: Add http2errno

This patch adds a method to convert HTTP errors returned by Meshblu
to common Linux errors. All protocols driver implementation MUST
return errors based on errno in order to achive compatibility between
the core and different protocol implementations.

CESARBR/knot-service-source,CESARBR/knot-service-source,CESARBR/knot-service-source,CESARBR/knot-service-source,CESARBR/knot-service-source