STF467 corrections:

- Add new component variable for emergency service (support of urn)
- Add new PIXIT for security algorithms
- Consideration for AKA algorithm in respect to Credential calculation function
- Consideration for urn support in respect to f_setHeadersOnReceiptOfResponse function
- Support of contact header field in f_RemoveRegistration
- Use of key attribute for m_media_dynPT
- Consideration of encrypted SDP in MessageBody