Enable more flexible binding searches

[dmikusa]

Describe the Enhancement

libpak provides ways to search for bindings based on the name, type and provider (exact match). We should add a more flexible method that takes a callback. If the callback returns true, then it matches. If the callback returns false, then it doesn't match. This would allow buildpacks to have more control over how they match bindings.

Possible Solution

See above.

Motivation

Provide more flexibility to buildpacks when matching bindings.