Recipe DX with cells

[seefeldb]

Trying out a recipe DX based on cells and some propagator ideas, but also looking like regular code for piepline-y graphs.

Groundwork:

• cells with same signature as signals
• Proxy for cells and cell values (results of .get() on a cell) to allow deep structures transparently
• [x lift, curry and other helper to turn regular functions into nodes (or propagators)
• destructuring into cells in input and output
• nested cells fully supported
• remember what (indirect) cells were read in a module invocation
• use that information for scheduling

Rewrite recipes:

• rewrite recipes to use this syntax

Next up then:

• serialize as graph
• sandbox code

[gordonbrander]

@seefeldb if helpful, here also is the sketch implementation I did last week, but failed to push due to getting covid #114

[jsantell]

Closing out stale PRs, please reopen if this is relevant