Summary:
This default CA bundle file hasn't been updated since 2016. Update it to the current cURL extraction.
I believe this is notably impactful because of a new "Let's Encrypt" certificate, but didn't hunt down the particulars.
Test Plan:
Confirmed the hash matches the published hash:
```
$ openssl dgst -sha256 resources/ssl/default.pem
SHA256(resources/ssl/default.pem)= ae31ecb3c6e9ff3154cb7a55f017090448f88482f0e94ac927c0c67a1f33b9cf
```
This assurance is fairly meaningless since both the hash and file are published on `curl.se`. It didn't get corrupted by stellar radiation before it made it into Git, at least?
Differential Revision: https://secure.phabricator.com/D21739
Summary: Ref T13395. Moves all remaining code in "libphutil/" into "arcanist/".
Test Plan: Ran various arc workflows, although this probably has some remaining rough edges.
Maniphest Tasks: T13395
Differential Revision: https://secure.phabricator.com/D20980