Restructure interpreter + analyzer ns

[borkdude]

As preparation work for #417 we need to restructure the namespace structure of interpreter and analyzer into something which makes it easier to refer to interpreter functions from the analyzer instead of vice versa.

Possibly:

interpreter.cljc -> analyzer.cljc
analyzer.cljc -> evaluator.cljc

So the interpreter invokes the analyzer (like now) but many functions from the interpreter namespace go to evaluator, which is referable by the analyzer.