Use obf_id to create IDs

[briangow]

These PRs should be merged before the one I'm opening here: #44 , #50 , #53, #56 , #57 . The PR being opened here was built on top of those PRs in an attempt to avoid lots of merge conflicts (especially with #56). This PR can be reviewed by checking 440e955.

This PR makes use of the obfuscation function introduced in #50. It replaces instances of FARM_FINGERPRINT(GENERATE_UUID()) which created 64 bit integers that could be negative and varied from build to build. The goals of this new approach are to:

• make the build repeatable by using a deterministic source for the obf_id function
• use positive IDs
• where possible, limit the ID to 32 bits

The approach for identifying a deterministic source was to step through these options until a unique source was identified:

1. Use a unique ID from MIMIC if available
2. Use trace_id, which is generally unique
3. In cases where trace_id was not unique, combine it with another variable to make the combination unique

The instances of FARM_FINGERPRINT(GENERATE_UUID()) which set load_row_id were not updated as this column falls outside of the official CDM table columns.

[briangow]

Updated with 888cfef to add missing project and dataset references when calling obf_id_str.