[FEATURE] Add a link to delete the deprecation log file

This adds a link to delete the deprecation log file from the reports
module. It also changes the status check on the deprecation log
to always show the size of the file, not only when it's over limit.

Change-Id: Ic51014b9f59100b1550a969e39cfabd4735fe4ac
Resolves: #23387
Releases: 4.7
Reviewed-on: http://review.typo3.org/7069
Reviewed-by: Oliver Klee
Reviewed-by: Philipp Gampe
Tested-by: Philipp Gampe
Reviewed-by: Steffen Gebert
Tested-by: Steffen Gebert