0.3.0, release candidate 0

This is a release candidate for our 0.3.0 version. Let us know if you find any bugs! The big things to note since the last release is an implementation of Logitech Media Server as a full-fledged backend for AmpliPi, and support for our latest & greatest hardware (shipping soon!) There's also a host of bugfixes, documentation updates, and other errata. Please test it out and let us know if you have any issues!

What's Changed since the last pre-release

• update imaging docs by @rtertiaer in #520
• feat: add development flag to scripts/configure.py by @rtertiaer in #511
• Password CRUD; authenticated main UI by @rtertiaer in #518
• Fix Disconnected Zone Bug by @klay2000 in #528
• Etcher flashing docs by @klay2000 in #534
• Build Webapp Off Amplipi by @klay2000 in #533
• Prevent node_modules from being deployed by @rtertiaer in #536
• Update how-to GIFs by @SteveMicroNova in #550
• Implement Logitech Media Server in mainsteam AmpliPi by @rtertiaer in #549
• Actually update the zone's source id by @linknum23 in #557
• Preamp v4 Support by @Lohrer in #551

Full Changelog: 0.3.0-beta2...0.3.0-rc.0