Add redirect field to Python operations

[emmambd]

What problem is your feature request trying to solve?
In #309, redirect was added to the schema and CSV, but not the Python operations. That means right now, if I want to add redirect and still generate the right bounding box I need to

Add a feed via the add_gtfs_schedule_source or add_gtfs_realtime_source operations
Push PR
Modify JSON to include redirect directly
Update PR
rather than add all fields through the operations.

Describe the solution you'd like
Include redirect in Python operations, to add and update gtfs schedule and gtfs realtime feeds.
Include redirect object in schema in README

[emmambd]

@cka-y Looks like the test is validating for a string value, when redirect is a number: 4b71837#diff-92300112b36301d0886c9786601b64e36393c1ae3dd25102b2ce3af4cfb72795.

[cka-y]

Indeed! had to change it to number because of preexisting feeds but forgot to update the tests.

[emmambd]

@cka-y Looks like this is breaking Fred's script:

Traceback (most recent call last):
46 File "", line 2, in
47 File "/home/runner/work/mobility-database-catalogs/mobility-database-catalogs/tools/operations.py", line 142, in add_gtfs_schedule_source
48 catalog.add(**data)
49 File "/home/runner/work/mobility-database-catalogs/mobility-database-catalogs/tools/representations.py", line 168, in add
50 if len(redirects) > 0:
51 ^^^^^^^^^^^^^^
52 TypeError: object of type 'NoneType' has no len()

Are the operations not set up to take the redirect as an optional field? The script run we did last night had 0 redirect fields populated.