Fix vulnerabilities, revert node-fetch to v2, significantly reduce api calls per profile.

[10Nates]

• There were numerous vulnerabilities identified by npm audit, reduced 31 vulnerabilities down to 0.
• node-fetch is ES6-only on v3+, reverted it back to v2. @jishanshaikh4's fix does the job.
• A significant amount of API calls per request were duplicates. Brought them down from 7 to 3 calls per profile request by...
  • combining repoStars() + repoForks() into repoStarsAndForks().
  • passing reused calls through calc() into getProfile()