BibUpload: sensible history and other goodies

• Drops support for not documented and unbound option opt_tag.

• Drops support for unused (and complicating) CLI --stage option.

• Stores history only if a record is really modified. Includes a migration kit to remove useless history entries. (references #498) (closes #1250)

• Take use of new write_message lazy mode, that allows computing strings to print, only if verbosity level is reached.

• Introduce new CFG_BIBUPLOAD_DISABLE_RECORD_REVISIONS flag to control whether it is desired to optionally disable keep track of record revisions in a history table (e.g. in case record updates are all coming from an external system which already keeps track of history). (closes #871)

• Minimize that handling of fulltextes to when the incoming record refers to 8564 tags or contain FFT tags.

• Since the 005 timestamp granularity is of the order of seconds, properly introduces sleeping points of 1 second, in case a record is modified a second time within the same second.

• Removes try..except: clauses that were capturing all exception and just logged them as warning.

• Additionally takes care of properly update record timestamp only if there was really a metadata update or at least one FFT tag.

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