Add support for interacting with batch signatory

[haysch]

Batch signatory is a new feature that allows combining multiple signatories across one or more signature orders,
and then perform a single batch operation, i.e., signing or rejecting.

Additionally, OIDC evidence provider has been marked as deprecated.

[mickhansen]

After merge, on master:

npm version minor
git push --tags origin master

and then create a new release via github relases