Support importing tar/gz databases

[aeisenberg]

Currently, we are able to import databases that are zipped, but our current unzipper library does not support tar-ed databases. I'll have to look deeper to see if this is a limitation of the library or if we are just using it in the wrong way.

Generally most codeql dbs are zipped and so this isn't a problem, but some dbs created by third parties are in other formats. It would be great to be able to import them as well with no hassle. For example, see here: https://bug-bounty-codeql-databases.s3.us-east-2.amazonaws.com/index.html

[aeisenberg]

Looks like to get this working, we'll need to use a different library for extraction. This one could possibly work.

https://github.com/npm/node-tar