feat(#1450): add --skipBin to limit compilation of hybrid deps

[daylinmorgan]

This implements a new flag --skipBin, so that we can run nimble build|setup|install without also compiling hybrid dependencies.

In the current implementation, subsequent runs don't attempt to compile the binary for example:
nimble setup --skipBin && nimble setup doesn't result in hybrid dep binaries being compiled.

I'm not sure if that is what we want, let me know if any invocation without --skipBin should result in compilation of the hybrid deps. In which case I think I need to adjust the heuristics in solveLockFileDeps.

Closes #1450

[jmgomez]

In the current implementation, subsequent runs don't attempt to compile the binary for example:
nimble setup --skipBin && nimble setup doesn't result in hybrid dep binaries being compiled.

IMO when --skipBin is not present, it should check if the binary exists and if it isnt, build it.

Wether to approve this or not, it isnt my call. cc @Araq @arnetheduck

[daylinmorgan]

IMO when --skipBin is not present, it should check if the binary exists and if it isnt, build it.

I agree, this make more sense, and is certainly how I would imagine users would expect it to work.
I've updated packageExists to ensure the binaries are present and if not it reinstalls the package, and thus builds the binaries as expected.