Add recursive imports, add @zkemail npm imports, fix github link imports

[Divide-By-0]

Ready to merge! Preview available on https://zkemailrepl.onrender.com.

Changes I made:

• previously only 'blob' in github links was handled right. now 'tree' in github links is handled correctly also.
• files that import other files that are all circomlib or in @zk-email packages, are imported correctly
• All external imports are at /external so relative to root. resolves the double import problem i.e. x imports y and z imports w imports y would otherwise cause a double definition of y otherwise. works for imports on different depths.
• circomlib also imported from root regardless of level of import it appears in, making complex import hierarchies still work

Future to-dos:

• Import any npm package correctly by sourcing what the git url is automatically from npmjs, instead of one-off packages to url mapping being in this libraries.ts file.