Add some date Fields for software and OS Versions

It is very hard to maintain every bit of codes in a maintained state in a fairly big infrastructure.

The idea is to create some kind of reports with all OS and software, with a state of obsolescence

But by default, Software and OS have no date fields.

So, this contribution aims to add for those products a bunch of new fields :

• Release date
• Public full support end date
• Public normal end of support (this is mostly "the" date)
• Public extended end of support
• Specific end of support date (in case of a particular situation). If empty, this field 'copy' the 'normal end of support'