Support fluid tanks

[fechan]

You can check if a peripheral supports fluid_storage by checking if it has the fluid_storage function. https://tweaked.cc/generic_peripheral/fluid_storage.html It's nil if it doesn't versus if it's empty, then it's an empty table.

The easiest way to implement is probably to initialize a new Group when a peripheral is added with an optional attribute fluid. If the CC pipe manager sees a pipe between fluid groups, it should use pushFluid() instead.

The editor will need to know not to combine fluid groups with non-fluid groups.

[fechan]

This PR adds support for fluid tanks and fluid piping.