Improve usability: aggregated package or cli

[andyfangdz]

Creating this issue here as a note of what we discussed on Friday:

Right now, to use vx, one has to pull in each of the dependency as individual repositories. To improve the usability of the package (e.g. upgrading to a new version of vx), we can consider two approaches:

1. Create an "aggregated" package, e.g., @vx/vx, as an indexing package of all the components in vx. This is the same approach as lodash (https://github.com/lodash/lodash#installation).

2. Create a CLI that manages @vx/*.