updatexlrator.cgi: Fix Bug 10477 - Update Accelerator disk usage statistics are very...

updatexlrator.cgi: Fix Bug 10477 - Update Accelerator disk usage statistics are very cramped in 2.15 beta1

- This bug has been open for a long time and is still valid. The Cache statistics on
   the Update accelerator configuration page are jammed closely together making it
   not so easy to see what the numbers are.
- Implemented similar approach as used on the Memory table section of the Memory
   information page.
- Installed on vm testbed machine and confirmed to provide the desired layout.

Tested-by Adolf Belka <adolf.belka@ipfire.org>
Signed-off-by: Adolf Belka <adolf.belka@ipfire.org>
Reviewed-by: Bernhard Bitsch <bbitsch@ipfire.org>
Tested-by: Bernhard Bitsch <bbitsch@ipfire.org>
Reviewed-by: Michael Tremer <michael.tremer@ipfire.org>
Signed-off-by: Arne Fitzenreiter <arne_f@ipfire.org>