2.50.07: Improve validations; add emissions totals

This is a patch update with minor improvements to how the API ingests, calculates, and returns data for building assemblies.

This update moves some code over from our bill of materials-based LCA repo to improve how units are declared and interpreted. Parts of the API still use implicit units. Allowing explicit unit declarations also supports our use of more complex units (e.g., thermal resistivity) for performing insulation takeoffs.

In the responses for each assembly, we how return total (A-C) emissions for that assembly. This wa a request related to improving visualization of these impacts.

The endpoints which return carbon intensities by assembly now validate the passed ID against a list of valid IDs. Previously, a user could pass silly strings and potentially trip an uncaught error.