Added alarm features for DS3231

[mfulz]

I've implemented missing features for DS3231 RTC similar like RTClib

These can be used to set Alarm1 (alarm2 is missing), read alarm1, activate alarm1, use sqw for interrupts, etc.

[deadprogram]

@conejoninja PTAL :smile_cat:

[conejoninja]

it's on my backlog, i'll review it eventually

[mfulz]

Hello, thanks for your contribution, since you already did the work for Alarm1, does it make sense to add Alarm2 too?

Also, since we are at it, I would add a new example under /examples/ds3231 for the alarms, let's keep the one already as "basic" and another for the alarms. It would be great to show how to set an interrupt on TinyGo.

Hi sure can do that stuff, if it's fine around 2-3 weeks as timeline. And of course alarm2, examples, docs will be added. Just wanted to make sure, that the PR will be accepted before doing the whole work :)

[conejoninja]

Sure, we welcome every contribution, sometimes we are a bit slower reviewing changes, but we eventually get them done.

[gKits]

Hi @mfulz are you still actively working on this? I can assist if needed.

[deadprogram]

Closing now that #805 was merged. Thank you!