Soil test quick form

Follow up to #2784911: Add individual fields for specific soil test measurements → , which added a Quantity Measurements field to Soil and Water test logs, allowing individual soil test result data points to be stored in farmOS for future comparison across tests and time periods. This added the storage capability, but it did not provide any tools for making it easy to manually enter soil test result data in a standardized way.

Proposed solution:

Create a "Soil Test Results" quick form that exposes specific fields for all the various data points we might want to collect, and then maps those into quantity measurements on the soil test log that is created.

This provides a nice prescriptive way to collect the data, while still keeping the underlying soil test log type very generalized. And it means that we can leverage general tools like the Quantity Report Generator to analyze trends in the soil test quantity measurements over time.