IP Scanner: Resizeable columns

As per title to be fair.

It doesn't appear we can increase the width of columns (manually or by double-click 'snap'), so am unable to view the full FQDN of hosts.

Start by opening the IP Scanner view and reproducing the host-table problem with a long FQDN. Inspect how its columns are configured and verify that users can resize them manually and by double-clicking to fit content; done means the full FQDN can be viewed.

索引モデルが issue の本文から書いたものです。