cli - import and doc issues #19

The instructions found on the docs page for import only work for 2/4 suggested paths:

• Spotify Extended Streaming History - format detects okay and import works
• lastfm-to-csv - format detects okay, 0 scrobbles found, n bad timestamp
• ghan64 (csv) - format detects okay and import works
• ghan64 (json) - format detects okay, 0 scrobbles found, n missing title or artist

Issues:

For lastfm-to-csv, the UTC Timestamp is exported as a date string in the format "DD MMM YYYY, HH:mm". The cli expects both a different field name, as well as a numeric time since epoch value. I'd either add compatibility for this time format, or remove the link from the docs.

For the ghan64 json, with large exports, the data is an array of arrays of scrobbles. the code currently expects just an array of scrobbles. i'd suggest refactoring and retesting with data. for a smallish output, i found out by accident (thanks autocorrect) that the user 'asylum' only has 7 pages of entries. Otherwise, i'd suggest explicitly calling out csv outputs from the exporter on the docs page.