Add lifetime storage settings for indexDB / localStorage

[pes10k]

We currently set a max lifetime of 7 days for JS set cookies. It would be good to add some similar lifetime-ing of other JS-set storage (i.e. localStorage, indexDB).

Might also make sense to key off of whether the JS is 1p or 3p (not the frame / context, but the JS code source)

[fmarier]

See:

• https://cs.chromium.org/chromium/src/content/browser/storage_partition_impl.cc?l=197&rcl=bd076e2ce224dcf04b3a477559c3a4cd2e6e97d0
• https://bravesoftware.slack.com/archives/C6YNM6Y5S/p1576017118172600?thread_ts=1576011656.169800&cid=C6YNM6Y5S

[fmarier]

The latest version of ITP does the following:

Now ITP has aligned the remaining script-writable storage forms with the existing client-side cookie restriction, deleting all of a website’s script-writable storage after seven days of Safari use without user interaction on the site. These are the script-writable storage forms affected (excluding some legacy website data types):

• Indexed DB
• LocalStorage
• Media keys
• SessionStorage
• Service Worker registrations

[pes10k]

Just adding (bc i couldn't tease it out from the blog post), Safari now does this for all sites, not just ITP-labeled domains.

Also, interesting implementation detail, 3p w/o storage access don't get a timer (e.g. seeing the same 3p on the same 1p doesnt' reset the timer for the 3p's storage)