CLI command to copy a block from the block collection to the current project

**Is your feature request related to a problem? Please describe.**
Give developers and easy way of adding block collection blocks to their boilerplate based projects

**Describe the solution you'd like**
A cli command along the lines of `aem install block ${blockName}`

**Describe alternatives you've considered**
My hunch is today this happens in one of 2 ways, a local checkout of block collection (that then needs to be kept up to date) or going to GitHub and copying file contents manually. Neither of those is overly cumbersome, but this would just add a small improvement to that workflow.

In terms of naming the command, I like using `install ${sub-command}` because it allows a bit of future extensibility for future sub-commands we may want to support (sidekick plugins, for example)

**Additional context**
Add any other context or screenshots about the feature request here.