chore(buffers): potentially allow configuring max record size, max data file size, etc

[tobz]

As seen in #13102, we have users whose sources may easily ingest enough events in a single go to generate an EventArray that may exceed our configured default limits. While we're going to change the default maximum record size to make the defaults a bit more flexible, we still need a more holistic solution to this problem.

We should investigate the feasibility of allowing values such as the maximum data file size and the maximum record size to be changed by the users via the configuration.

In general, we can (and in some cases, already do) enforce the required invariants between the values, such as making sure the buffer size is greater than or equal the maximum data file size, and so on. We would need to more stringently do so, though, ensuring all values are constrained in whatever way is necessary.

Additionally, and perhaps most important, we would need to investigate if it was safe/possible to allow changing these values when the buffer already existed. In some cases, such as changing the maximum data file size, it would likely not be safe to do so, since much of the logic in the buffer depends on all data files having a uniform size limit, etc... so allowing these changes would possibly require changing the layout of the ledger, etc, essentially encoding the configuration of these values into the buffer in a write-once-read-many fashion.

This would let us at least provide the ability to change the defaults, and it would be up to the user to figure out a deployment strategy to roll out their changes i.e. new hosts that used the new value while old hosts were unchanged and then drained/rotated out of service, etc.