revise GFT lot zoning logic

[damonmcc]

resolves #741

successful build here, all build runs here

changes

The most significant change is to the model int_flags__zoning which now uses the new model int__zoning_districts. Since the diff is hard to read, here are links to the changed models: int_flags__zoning, int__zoning_districts.

Per chats with GIS, this also changes the final columns related to zoning districts to be most useful.

notes

Chose to put the new model in the /intermediate/flags folder to avoid creating a new yml file, but understand if it'd make more sense to move it up to `/intermediate'.

Notes on column changes in the final table:

• We had Zoning Districts for values and Zoning Districts Flag for flags, but the Flag column wasn't useful because virtually all values were Yes and the value column had the "GFT zoning district category" likeR1-R4
• Now we have Zoning Districts and Zoning Districts Category where the value column has the lot's actual zoning districts like R1-A and the Category column has the GFT category like R1-R4
• This allows the GFT tool to show the GFT category in the table and the lot's original values in the popup when a lot is clicked

DAG screenshot

[damonmcc]

for readability and our future selves, gonna pull out the zoning district logic from int_flags__zoning into a new model that feeds into it

[damonmcc]

@fvankrieken I changed the group/order bys to use column names rather than numbers and moved the last group by in int_flags__zoning to the last CTE

appreciate your suggestions for changing part of int__zoning_districts to use your preferred approaches, but it isn't worth holding up this PR which also fixes GFT being broken on main. let's save it for a follow-up