Make the Sort module a proper standard module

[jabraham17]

Currently, the Sort module exists in the modules/packages directory in the Chapel tree. This effectively works as a standard, always available to be imported module, with the caveat that the documentation shows up in a different location.

In an offline discussion today, we discussed moving the Sort module into module/standard. This would have no effect on user code today, but would change how our documentation shows the module. Ideally, when making this change, https://chapel-lang.org/docs/modules/packages/Sort.html should redirect to https://chapel-lang.org/docs/modules/standard/Sort.html in some way.