Reconciling Data.Nat.Divisibility.Core._∣_ and Algebra.Definitions.RawMagma._∣_

[jamesmckinna]

The substance of the issue (for the additive fragment of Nat) is already discussed in #1919, but that issue can (should!) be closed by merging #1948. So this is a placeholder to work on this specific problem in the multiplicative fragment of Nat.

Carrying over the summary from #2013:
Two Three parts to this:

• low-hanging fruit: added pattern synonym and consequences/uses of it to Data.Nat.* (merged in Reconciling Data.Nat.Divisibility.Core._∣_ and Algebra.Definitions.RawMagma._∣_ #2013)
• higher-hanging fruit: reconcile the two definitions of _∣_ for the Data.Nat.Base.*-rawMagma instance
• knock-on changes for Data.Integer.Divisibility.* and Data.Rational.* only if the preceding step succeeds

cf. #679