fix: export all properties under the root instead of default

[stephen-slm]

By exporting under the root, javascript importing modules will continue
to use it as expected without first having to index .default.

[coveralls]

Coverage increased (+0.2%) to 85.696% when pulling 8405162 on stephensli:fix/root-export-wrapped-solcjson into 46c59df on ethereum:master.

[ekpyron]

Ok, since argotorg/solidity#12585 passes its tests relative to this change, I'm merging this, but @cameel and @axic should still have a look at it as well.

[cameel]

Looks like this PR was enough to make it work with Truffle. For me it still fails with Hardhat though. That's because of the dist/ directory that's now in the package.

I rebased #594 on top of this and all its tests should be passing if things are fixed. The truffle ones just need further adjustments so please ignored them until I fix them but I think the issue in the Hardhat ones is real.