Track published/modified date for debian data

[wagoodman]

Today the debian DSA data has looks like this (in the workspace input dir):

[11 Nov 2024] DSA-5811-1 mpg123 - security update
	{CVE-2024-10573}
	[bookworm] - mpg123 1.31.2-1+deb12u1
[11 Nov 2024] DSA-5810-1 chromium - security update
	{CVE-2024-10826 CVE-2024-10827}
	[bookworm] - chromium 130.0.6723.116-1~deb12u1
[11 Nov 2024] DSA-5809-1 symfony - security update
	{CVE-2024-50340 CVE-2024-50342 CVE-2024-50343 CVE-2024-50345}
	[bookworm] - symfony 5.4.23+dfsg-1+deb12u3
[11 Nov 2024] DSA-5808-1 ghostscript - security update
	{CVE-2024-46951 CVE-2024-46952 CVE-2024-46953 CVE-2024-46955 CVE-2024-46956}
	[bookworm] - ghostscript 10.0.0~dfsg-11+deb12u6

From this we could derive at least publication date, and maybe discern modification date if a CVE is listed multiple times (needs investigation).

This will require the OS schema to be updated to allow for these kinds of fields #266

[wagoodman]

Open question: how can we get this information for unsupported versions (e.g. debian 7)?