Add antigravity support to gravity

[DL6ER]

What does this implement/fix?

Add support for subscribed allowlists. To differentiate between lists that block and those that allow, we add a new column type which is an enum with values 0 (block) and 1 (allow)

Related issue or feature (if applicable): N/A

Pull request in docs with documentation (if applicable): N/A

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Checklist:

• The code change is tested and works locally.
• I based my code and PRs against the repositories developmental branch.
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[pralor-bot]

This pull request has been mentioned on Pi-hole Userspace. There might be relevant details there:

https://discourse.pi-hole.net/t/use-to-whitelist-in-abp-style-adlists/63603/63

[PromoFaux]

(rebased to fix tests)

[PromoFaux]

Seemingly the upgrade does not add in the vw_antigravity, I had to recreate my gravity db with pihole -g -r recreate in order for the new views to populate

(edit: And like an idiot I didn't backup my v16 db)

[github-actions]

This pull request has conflicts, please resolve those before we can evaluate the pull request.

[github-actions]

Conflicts have been resolved.

[yubiuser]

All the changes in 15_to_16.sql should be moved to 16_to_17.sql as they are unrelated to abp_entries.

Comments addressed