Research initialised RAM

[tkers]

As an extension of #283, we can look into supporting initialised RAM as mentioned in https://www.taygeta.com/forth/dpanse.htm#E.5.

This would either mean that the words , (comma) and c, (c-comma) are able to "write" into RAM memory space at compile-time (in addition to ROM), or that some other mechanism is available to initialise RAM in an easier way.