Replace bash scripts and aws instruction with the cc-downloader

[lfoppiano]

As discussed in https://github.com/commoncrawl/issues/issues/625:

• provide instruction using the polite cc-downloader
• remove awk-based download script
• remove AWS s3 instructions

[wumpus]

cargo install cc-downloader doesn't always work -- it doesn't work on rf, for example. So near where you mention installing cc-downloader, I'd mention that users should look at the cc-downloader repo for installation instructions if cargo install cc-downloader does not work.

[lfoppiano]

cargo install cc-downloader doesn't always work -- it doesn't work on rf, for example. So near where you mention installing cc-downloader, I'd mention that users should look at the cc-downloader repo for installation instructions if cargo install cc-downloader does not work.

ahhh, good catch @wumpus!

I've added the same fix also in the whirlwind-python PR.

[sebastian-nagel]

Thanks, @lfoppiano! Looks good.