Clarify commandline usage instructions & don't double process geosonl

[yuletide]

Current output

mtsds --configure
Run mtsds with valid options:
--config filename.geojsonl,
--convert filename.geojsonl,
--sync,
--token,
or --estimate

Implies that the tool is looking for geojsonl as input for both --config and --convert steps. However, if I run mtsds --config input.geojsonl it then re-converts it, giving me input.geojsonll.

As a user with (most likely) a .geojson input file this is a bit confusing, esp if I haven't read the docs lately.

In summary:

• Usage should specify .geojson for --config step (and convert also?)
• [Feature Reuest] --config runs on both, only converts to geojsonl if needed (no .geojsonll)

[jbranigan]

Reopening: usage instructions are updated, but --config and --convert still need file inspection & handling