BibUpload: smart record uploader

• Adds bibupload_revisionverifier submodule to compare the submitted record revision information (stored in MARC tag 005) against the list of known archived revisions of the record, in order to generate a record patch. (Useful when cataloguer modifies an older version of a record while another cataloguer touches the record in question, because revision verification step will now merge the two wanted changes together). As a side effect, the --replace mode of bibupload will be always changed to --correct mode with the wanted record patch. In case of conflicting needs (when two users modified the same fields), the bibupload ends with an error and submits the given modifications to the holding pen. (closes #816) (closes #864)

• Implements field deletion in bibupload based on DELETE_CODE and DELETE_VALUE set for the field. (closes #897)

• Updates DB only for those elements that are modified in the submitted version.

• Drops support for not documented (and no longer used) FMT tags.

• Deprecates support for --reference/-z in favor of --correct/-c.

Co-authored-by: Samuele Kaplun <samuele.kaplun@cern.ch>
Signed-off-by: Samuele Kaplun <samuele.kaplun@cern.ch>
Tested-by: Tibor Simko <tibor.simko@cern.ch>