[Feature] Make --event-end-time require --event-start-time and vice versa

[QMalcolm]

Currently, we have five ways to run a microbatch model 🥴

1. creating/recreating the model
   • batches are run from model's defined begin to "now"
2. incrementally with no extra args
   • the batches run are determined by the current time and the lookback
   • f.x. if you have a batch_size=day, lookback=2, and it is "currently" 2024-10-17 13:04:39 then three batches are run: 2024-10-15, 2024-10-16, and 2024-10-17
3. incrementally with both --event-time-start and --event-time-end specified
   • batches are run >= --event-time-start and < --event-time-end
   • f.x. if you have a batch_size=day, --event-time-start "2024-10-01", and --event-time-end "2024-10-04" then three batches will be run: 2024-10-01, 2024-10-02, 2024-10-03
4. incrementally with only --event-time-start specified
   • batches will be run from --event-time-start to "now"
   • f.x. if you have a batch_size=day, --event-time-start "2024-10-13", and it's currently midday on 2024-10-17, then five batches will be run: 2024-10-13, 2024-10-14, 2024-10-15, 2024-10-16, and 2024-10-17
5. incrementally with only --event-time-end specified
   • batches will run the --event-time-end batch plus prior batches according to the period
   • f.x. if you have a batch_size=day, lookback=2, and --event-time-end "2024-10-04", then three batches will be run: 2024-10-01, 2024-10-02, 2024-10-03

Through further discussion, we believe (4) and (5) are confusing, unexpected, and dangerous. Ways (4) and (5) weren't intentional implementations, but accidental realities created by implementations for (1), (2), and (3). As such, we should require that the specification of --event-time-end necessitates --event-time-start and vice versa.

[mirnawong1]

docs pr here to address this: https://github.com/dbt-labs/docs.getdbt.com/pull/6351/files