feat(core): Filter requests matched by a route handler

[offirgolan]

Description

Filter requests matched by the route handler with a predicate callback function.

The callback will receive the request as an argument. Return true to match the request, false otherwise.

Multiple filters can be chained together. They must all return true for the route handler to match the given request.

Motivation and Context

This can be useful when trying to match a request by a part of the url (e.g. a query param), a header,
and/or parts of the request body.

Types of Changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist

• I have added tests to cover my changes.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• My code follows the code style of this project.
• My commits and the title of this PR follow the Conventional Commits Specification.
• I have read the contributing guidelines.