scripts: Use local server for Strava auth
scripts: Use local server for Strava auth

Several changes combined into one:
 • Redirect back to the local server to complete the auth flow, rather
   than pointlessly redirecting via an AWS server
 • Convert the temporary token into a long-term token so that people
   don’t have to reauthenticate every time they want to upload an
   activity
 • Don’t use a fixed local port — allow the OS to allocate us one
 • Store the access and refresh tokens in the correct directory
   according to the XDG Base Directory specification
   (https://standards.freedesktop.org/basedir-spec/basedir-spec-latest.html)

I’ve registered a new application with Strava for doing the
authentication, since the client secret is needed.

Signed-off-by: Philip Withnall <3ba3974e96044dcde818e6310ed799abe10671d4@tecnocode.co.uk>

Tigge/antfs-cli