Previously, the endtime-starttime interval being processed by the
`run_as_update` method would shrink by 1 (second) with each recursion.
This ultimately broke `run_as_update` when processing anything other
than 1-second data, but it wasn't obvious because we rarely had to
actually recurse. There is a little trickery now to ensure that user-
provided starttime and endtime are inclusive of the full first
(most recent) update interval, while subsequent, calculated, endtimes
are set equal to the prior starttime minus specified output_interval
(e.g., 'second', 'minute', etc.).

It turns out that none of the factories currently being used in
production expects bytes as input, and in fact, Util.read_url()
converts everthing to a string anyway, so a BYTES-oriented input
would couldn't not possibly be working. So, just remove all use
of BYTESIO, and instead use only STRINGIO.

This is a bandaid to allow the `--input-url` option to be used to
read in single files. It adds zero functionality beyond what already
existed when the `--input-file` option was used.

The original merge request had an extra indentation space that the
black formatter didn't like.

A new FGE+ObsRIO test system is being deployed to Honolulu.
For now, we simply create an entry in Metadata.py so that
variationfiltering can be be applied to these new data. The
calibration parameters are defaults for non-high-latitude
FGE fluxgages.

A new FGE+ObsRIO test system is being deployed to Guam. For now,
we simply create an entry in Metadata.py so that variation
filtering can be be applied to these new data. The calibration
parameters are defaults for non-high-latitude FGE fluxgages.

GUA is transitioning to an ObsRIO data logger, which requires a
metadata entry in Metadata.py. We do not know actual calibration
values for the GUA Narod mag, and cannot retrieve them currently
due to ongoing communication issues, so we'll use Narod default
calibration parameters.

This commit applies strictly to GUA. Additional commits are
forthcoming that relate to the test FGE+ObsRIO system that will
also be deployed soon.