CAMARA Common YAML: addition of common HTTP Headers for Device Identifiers

[Kevsy]

Problem description
CAMARA_common.yaml does not account for Device Identifiers being provided as HTTP headers. Use of HTTP Headers is a recommendation in the API guidelines -
POST or GET for transferring sensitive or complex data:

"When using GET, transfer the data using headers, which are not routinely logged or cached"

Possible evolution
Add reusable parameter definitions for these HTTP headers in CAMARA_common.yaml

Headers are typically Uppercase/hyphen-separated, and are documented that way in the HTTP Headers Definition section of the guidelines. Hence Device Identifier HTTP Headers would follow this convention:

IPv4-Address
IPv6-Address
Network-Access-Identifier
Phone-Number

Alternative solution
Define Device HTTP headers in each relevant CAMARA spec, which risks misalignment.

Additional context

[Kevsy]

Fixed in #120