Simplify add_metadata_to_imported_file
lots of changes to use exifread
Add some missing-data handling. currently ignores missing data
add logging for ignoring missing data
add 'unknown' as defaults for missing place info so photos still show up when filtering by metadata
let's be exact
allow staging to arbitrary dir
use real filename to avoid clashes
typo
Use more sortable filenames, and uppercase file extensions to guarantee content dedup.
add rename script, unnecessary with current import but maybe useful to keep around