Update filenames for config and database about ashirt

[jrozner]

The follow will need to be run as a manual upgrade step:

mv ~/Library/Preferences/ashirt/screenshot.json ~/Library/Preferences/ashirt/config.json
mv ~/Library/Preferences/ashirt/screenshot.sqlite ~/Library/Preferences/ashirt/evidence.sqlite

[jrozner]

This was merged as part of #39. The following manual changes need to be made:

mv ~/Library/Preferences/ashirt/screenshot.json "$HOME/Library/Application Support/ashirt/config.json"
mv ~/Library/Preferences/ashirt/screenshot.sqlite "$HOME/Library/Application Support/ashirt/evidence.sqlite"

We also are by default moving the storage of evidence to $HOME/Library/Application Support/ashirt/evidence. Not change is necessary here but is an option in the migration.