migrate strike creation to buefy steps

Closes #16 and #15

See merge request !2

Merge branch '15-use-steps-for-strike-creation' of git.fridaysforfutu.re:open-data/frontend into 15-use-steps-for-strike-creation

Sometimes strikes wouldn't load properly in the strike list...
Not anymore :)

See the title, fixes #23

The mail and phone number now gets autocompleted :)

Strikes can now be really deleted :)

The parsing is now better (or work's at all) and the error handling for
missing date inputs is now better (i.e. is there at all)

Fixed an unknown login bug where token wouldn't refresh when resuming
a session

Fixes #20

This makes the strike list not take up the whole width on desktop.
Actually also fixes #18 on mobile :)