Explain timestamp rounding and offset to the user
Explain timestamp rounding and offset to the user

Added some text on the time series form to explain what is meant by
timestamp rounding and timestamp offset.

kickapoo/enhydris,ellak-monades-aristeias/enhydris,aptiko/enhydris,aptiko/enhydris,ellak-monades-aristeias/enhydris,openmeteo/enhydris,kickapoo/enhydris,openmeteo/enhydris,ellak-monades-aristeias/enhydris,aptiko/enhydris,openmeteo/enhydris,kickapoo/enhydris