Better Layout for Artifact Download Box

The download box in Archiva behaves not well regarding following conerns:

• box is too small, in any case with our namin conventions where artifacts may have up to 20 characters
• size is display in raw byte value, which is more confusion than useful when sizes become bigger
• when several artifacts for a given version, only distinguished by classifier, are deployed in repository, not clear hint is display to recognized them

I tried to improve this issues with folloowing changes:

• enlarged box to 280px (CSS and images)
• display size in KB, MB, GB depending on effektive size
• added classifier next to type when available

Hope this path may be use fule for Archiva team and would be applied for one of the next maintenance releases.