Migrate to c2pa-rs unstable API

Changes in this pull request

Migrates to c2pa-rs unstable API.

TODOs are scattered around with various blockers and changes. Here's a list of some of the critical ones:

[x] Need methods to iterate all manifests and all resources in manifest contentauth/c2pa-rs/pull/482
[ ] Need method to set builder base path ok-nick/builder_base_path
[ ] Need method to normalize identifiers (preferably a struct/enum wrapping them)
[ ] Need methods for fetching manifest certificates & tree structure

Check the TODOs for more information.

[ ] Converting structs (Ingredient, Manifest, Reader, etc.) to json shouldn't pretty print (include \n, etc.)
- Rust has a format such as {:#?} for explicitly requesting pretty print
- The reason this is useful is when we need to convert the json string back to struct and the formatting is interfering
[ ] Constructing builder and ingredients is difficult and often results in repeated serialization and I/O
- It's also confusing to have to operate on the ingredient returned by add_ingredient (like for setting base paths)

Added --unknown flag when extracting resources to extract unstandardized labeled data (in addition to standardized labels such as thumbnails)
WIP: Specify separate sidecar path/dir if you only want a binary manifest as output #134
WIP: Don't rely on file extensions #150

[ ] This PR represents a single feature, fix, or change.
[ ] All applicable changes have been documented.
[ ] Any TO DO items (or similar) have been entered as GitHub issues and the link to that issue has been included in a comment.