Add sym/cmp/dev for DS3231M/S

[ubruhin]

SUMMARY

Adding DS3231 RTC as requested in https://librepcb.discourse.group/t/find-an-rtc/960:

DATASHEETS / REFERENCES

• https://www.analog.com/media/en/technical-documentation/data-sheets/DS3231.pdf
• https://www.analog.com/media/en/technical-documentation/data-sheets/DS3231M.pdf

OPEN QUESTIONS / UNRESOLVED ISSUES

It seems Maxim is now Analog Devices, but the datasheet is still from Maxim so for now I added these devices to the Maxim library.

CHECKLIST

• I have read and followed the library conventions¹.
• [na] For packages, I followed IPC7351C (see details in library conventions).
• [na] For modified elements, I bumped their version number².
• I already used the new library elements in a design and verified their correctness (optional).
• I'm the copyright owner of the added content (i.e. the changes are made by myself, not copied/imported from somewhere else).
• I agree to publish all my changes under the CC0 Public Domain License³, allowing everyone to use and modify the content without any restrictions.

¹ Library Conventions: https://docs.librepcb.org/#libraryconventions
² Minor version bump if only metadata was modified (e.g. "0.1" -> "0.1.1"), major version bump if functional changes were made (e.g. "0.1" -> "0.2")
³ CC0 Public Domain License: https://en.wikipedia.org/wiki/CC0