Update main ReadMe & other docs with current architecture

[aufdenkampe]

We've unfortunately gotten behind on updating all of our documentation (outside of our release notes) to reflect cumulative changes since our v0.12 release in December 2021.

This includes the fact that our architectural diagram still includes InfluxDB, etc.

We also want to describe how we use AWS services for our deployment of Monitor My Watershed, while also describing how it isn't required if others want to use our repo for deploying their own data sharing portal or IoT platform.