Piq: parse integer-like literals as words with --piq-relaxed-parsing

Allow a string which prefix looks like a number (e.g. 1foo) to be parsed as a
word/string.

Without --piq-relaxed-parsing, it would be considered an invalid integer
literal.
Piq: fix handling of embedded modules

This fixes "unknown type" error when types are immediately reused in data
objects that follow the the embedded modules.