deepstream-6.3: PACKAGECONFIG updates

[dwalkes]

• Added 'nmos' PACKAGECONFIG setting for enabling/disabling inclusion of NMOS (Network Media Open Specification) support, which requires avahi to be built with libdns_sd in its PACKAGECONFIG.
• Added dependency for the 'azure' PACKAGECONFIG setting on azure-iot-sdk

This is a backport of https://github.com/OE4T/meta-tegra-community/commit/79dea834cd0a04c7fd6399f8394905d759e707ce to deepstream 6.3

Resolves build error:

Running transaction check
Transaction check succeeded.
Running transaction test
Error: Transaction test error:
  file /usr/lib/libnss_mdns.so.2 conflicts between attempted installs of libnss-mdns-0.15.1-r0.armv8a_tegra and mdns-2200.100.94.0.2-r0.armv8a_tegra

[dwalkes]

@ichergui this resolves a build error on master branch for me. I've attempted to backport the relevant bits of https://github.com/OE4T/meta-tegra-community/commit/79dea834cd0a04c7fd6399f8394905d759e707ce to deepstream 6.3. Please confirm I've got this right.