[profiles] Add divide system profile

[watou]

The offset profile addresses addition and subtraction, but there are use cases for division and multiplication that should be addressed by a complementary system profile.

Some use cases can be addressed with UoM where the items use SI units and devices report in factors of 10 different from desired (such as a devices reporting tenths of Volts so specifying unit="dV" solves that). However other use cases cannot be addressed, such as reporting tenths of kWh but there is no suitable SI unit, or when there is no suitable UoM concept for the data.

See #3538 for further discussion. I can add other doc and UI PRs with some guidance. Thanks!

[J-N-K]

We had a discussion about that some years ago and the result was that only the most basic profiles should be part of core and other profiles should go into add-ons, see #779.

[watou]

@J-N-K I've read #779 and I believe this PR meets its spirit and your comment above. To have the offset profile is only half of basic arithmetic (add/subtract), while adding this profile merely fills the absence of the other basic arithmetic operators (divide/multiply). I don't think overloading the offset profile as proposed in #3538 was appropriate, but the need discussed was never met. I agree that all other manipulation (computation, string formatting, etc.) should go through the transformation path.