Bug fixing in topology discovery as part of CCVPN (Cross-Layer Cross-Domain VPN)...

1. Cross-layer tp-ttp relationship update.
2. Save te-link-attribute and label-restriction and relationship between them.
3. Add 3rd party controller id into network-id to make it unique for cross-domain use case.
4. Calling Base64 converter plugin to convert inter-domain-plug-id

Issue-ID: SDNC-899
Signed-off-by: Hesam Rahimi <hesam.rahimi@huawei.com>
Change-Id: I892249f8197ceb0e2d32b35a521fdbb1b833010c

Former-commit-id: a3603b522c83ffd8e8cfc0f6451697dc89a5a9a3