Allow configuring EloquentOrderByToLatestOrOldestRector

[johnbacon]

Resolves #147.

• Allows an ALLOWED_PATTERNS array of strings to apply this rule to
• Adds additional test items for variable handling

Notes

• The way this is implemented, it will always change created_at columns (as it did before)
• Because static analysis cannot get the value of a variable, we instead allow for specifying variable names

Tested

• Current test scenario
• Scenario where no rule configuration is present

[driftingly]

We use composer docs to update the docs using symplify/rule-doc-generator. Can you ensure your changes are compatible?

[johnbacon]

@driftingly That should be done now! Thanks for the heads up, it wasn't compatible without changes.