Change rate limit to 5 minutes per webhook, not the current default 30

[nocturne1]

While "Updates are rate-limited to once every 30 minutes per entity to prevent overwhelming the endpoint", the actual rate limit for webhooks currently is:

If your private plugin's "Strategy" is set to Webhook, you can provide data to TRMNL's server up to 1x every 5 mins. Requests sent at a faster pace will receive a 429 rate limit response.

MIN_TIME_BETWEEN_UPDATES should be changed from 1800 to 300 seconds, or alternatively, have a configuration element to set it (with 300 as minimum).

[nocturne1]

Actually I see that it used to be 5 minutes until recent commits. The verbiage above suggests that each entity is a separate webhook event, but a pending PR suggests that they might be combined into a single webhook?

[nocturne1]

Ok, indeed it seems that their rate limiting is VERY sensitive, that even setting 300 seconds isn't enough - one has to go a bit beyond it to be reliable (330 seconds). And that's with just one entity. even though they seem to be combined before sending (?), it seems to still trigger their limits.

So it seems like it's probably not viable to have the project set an aggressive default like this. I've just gone ahead and pared mine back to 1 entity, and manually edited to be 330 seconds. Let's home TRMNL gives us a bit more leeway in the future.