Remove superseded date attribute in result XML

[dbeyer]

I propose to use a uniform format of the date and time for the following attributes of a <result> in a Results XML file:

• date (probably this means "creationdate" of this record)
• starttime
• endtime

Example:

<result benchmarkname="afltc" date="2025-12-27 14:23:39 CET" starttime="2025-12-27T14:24:43.481183+01:00"

[PhilippWendler]

starttime and endtime are the main attributes and have consistent ISO format. date exists only for backwards compatibility, you can ignore it.

[dbeyer]

Then I propose to make a commit to remove it and add the commit to the milestone for the Release 4.0 ;-)

[PhilippWendler]

Right, by now enough time has passed that we can remove it. I have marked this issue for the next major version.