pycardium/utime: add set_time_ms and set_unix_time_ms

This merge request adds millisecond variants of the set_time functions.

This can be useful in case one wants to change the time without desyncing the milliseconds by accidently resetting them to 0.

Added functions:

• utime.set_time_ms(ms)
• utime.set_unix_time_ms(ms)