Leftover work from 0.12 release

[lewfish]

Here are some rough notes on lower-priority things I wanted to do in the 0.12 release, but didn't have time for.

• docker image badge broken (Fix or remove broken quay badge from README #1587)
• code coverage broken
• RVPipeline -> GeoMLPipeline and rv.core -> rv.geoml?
• ability to use model bundles with plugins that aren't installed but aren't actually used by any configs (Do not require every plugin recorded in the model bundle to be installed when using it #1916)
• predictor is kinda inelegant and might not work with other backends
• bad edge predictions when chip size doesn't divide prediction image size esp. on right side?
• more links to RV source code in docs, esp. from class names
• collapse api.rst and pipeline.rst docs
• document upgrader mechanism and plugin versions (Document config upgrader mechanism #1917)
• shrink docker image if possible (Update Docker build to improve caching and image size #1866)
• don't hardcode /opt/data/torch-cache
• more safety checks to make sure configs and plugins are registered correctly