Store snapshot of adblock lists during adblock list build and update

[ShivanKaul]

We are now downloading adblock lists to https://github.com/brave-experiments/adblock-lists-mirror/tree/lists/lists (after https://github.com/brave/devops/issues/11115). Next step would be to start using these downloaded lists instead of freshly downloading them as part of the build process.

EDIT: See comment below for better approach.

[ShivanKaul]

@antonok-edm came up with a better approach:

1. Download the lists during build time like usual
2. Validate like usual
3. Commit the new lists into https://github.com/brave-experiments/adblock-lists-mirror/commits/lists/lists
4. Use and ship the lists as usual

Now, if we want to find out what the lists looked like after a specific component update, we can find the adblock-lists-mirror commit associated to that build run.