Feature Request: Build Tools - Add command for generating zip bundles of each plugin from command line, locally

### Impacted plugin

Jetpack, Backup, Boost, Beta, VaultPress

### What

I would like to have the ability to generate a zip file of the plugins and be able to upload to a neutral site for smoke-testing a given branch

### How

Example proposed testing instructions

1. Standing on the root directory
2. Run `jetpack bundle boost`
3. Expect to find a` jetpack-boost-dev.zip` file inside the `build` directory
2. Run `jetpack bundle`
4. Expect to find these files inside the `build` directory
```
jetpack-backup-dev.zip
jetpack-beta-dev.zip
jetpack-boost-dev.zip
jetpack-dev.zip
jetpack-search-dev.zip
jetpack-social-dev.zip
vaultpress-dev.zip
```

Start at the repository root and trace the proposed `jetpack bundle boost` and `jetpack bundle` command entry points. Use the requested smoke-testing instructions as the acceptance criteria: plugin development ZIP files should be generated in the `build` directory, including the listed Jetpack, Backup, Beta, Boost, Search, Social, and VaultPress bundles.

Written by the indexing model from the issue text.