Address recurrent DNS queries

What's Changed

• add multiplexing information to guide by @sbSteveK in #541
• Add Cognito connect sample by @TwistedTwigleg in #536
• Split sample readme by @TwistedTwigleg in #544
• Update mainpage.md by @jmklix in #549
• Trivial documentation change by @TwistedTwigleg in #552
• CI and documentation generation adjustment by @TwistedTwigleg in #550
• Fix release script failing on releases with zero by @TwistedTwigleg in #553
• Mqtt5 shared subscription sample by @TwistedTwigleg in #556
• Shared Subscription sample readme adjustment by @TwistedTwigleg in #558
• Adjust MQTT5 and MQTT PubSub samples to output JSON by @TwistedTwigleg in #559
• Sample and command line refactor by @TwistedTwigleg in #563
• CRT update with DNS behavior improvements by @bretambrose in #564
• AutoTag PR for v1.22.0 by @TwistedTwigleg in #566

Full Changelog: v1.21.0...v1.22.0