Missing relay keys in bandwidth file spec

Not in spec or examples:

• relay_in_recent_consensus_count
• consensus_bandwidth
• consensus_bandwidth_is_unmeasured
• desc_bw_avg
• desc_bw_bur
• desc_bw_obs_last
• desc_bw_obs_mean

Not in spec:

• relay_recent_measurement_attempt_count
• relay_recent_priority_list_count

We need a specification for these keys so we know what they mean.