Use Available BagIt Manifests During Import

[mikejritter]

Resolves: https://jira.lyrasis.org/browse/FCREPO-3208

Updates Importer to use a preferred manifest based on all available in a BagIt Bag

---

To test:

1. Start a clean fedora instance
2. Create a binary resource in the new repository
3. Create a bag-config.yml with the following properites

   bag-info.txt:
   Source-Organization: fcrepo-import-export
   Organization-Address: localhost
   External-Description: Sample bag export for fcrepo-3208

4. Run the exporter using the default bag profile and a directory name fcrepo-3208

   java -jar target/fcrepo-import-export-0.4.0-SNAPSHOT.jar --mode export --resource http://localhost:8080/fcrepo/rest --dir fcrepo-3208 --binaries --bag-profile default --bag-config bag-config.yml --user fedoraAdmin:secret3

5. Create a sha256 manifest for the newly exported bag

   cd fcrepo-3208 
   find data -type f -print0 | xargs -0 -I {} sha256sum {} > manifest-sha256.txt                                                                                                                                               

6. Start a fresh repository
7. Run the import tool, with debug logging enabled to see the checksums used on import

   java -Dfcrepo.log.importexport=DEBUG -jar target/fcrepo-import-export-0.4.0-SNAPSHOT.jar --mode import --resource http://localhost:8080/fcrepo/rest --dir fcrepo-3208 --binaries --bag-profile default --bag-config bag-config.yml -u fedoraAdmin:secret3

8. Verify that the resource is in the repository and has a sha256 digest

   curl -u fedoraAdmin:secret3 http://localhost:8080/fcrepo/rest/86feb268-750e-4cde-9dcb-25e8197be1b6/fcr:metadata

[dbernstein]

@mikejritter : it would be helpful if you could add a recipe for running a manual test of this functionality as well. Like "1. fire up fedora 2. PUT resource A. 3. export bag ..." with command line calls for each step to facilitate testing. Thanks and nice work!