Change 3p storage handling to improve webcompat

[pes10k]

Currently Brave
1) doesn't send cookies to any sub-requests (excepting hardcoded exceptions), even for eTLD+1
2) doesn't allow any storage in embedded frames
3) nulls out storage related endpoints in embedded frames

All the above will cause webcompat problems.

We should maintain the same privacy protections, but decrease webcompat concerns, by making the following changes:
1) send cookies for eTLD+1 equal requests
2) all eTLD+1 equal frames have standard storage
3) eTLD+1 not-equal frames should have ephemeral (e.g. document length) storage

[pes10k]

closed in favor of #8514