Chain Metadata: require-bootstrap

[marcelovani]

We need to add a new metadata on the chains to tell the Chain Discovery whether a certain chain can be visible and executed when we don't have a Drupal site

Following the suggestions on this issue
hechoendrupal/drupal-console-extend-plugin#18
I think I like the idea of using require-bootstrap

For chains that do not need Drupal we could either set to false, i.e. require-bootstrap: false
If metadata is missing, the default value ) should be true.

Tasks:

• Do the issue Find a more relevant name for 'uninstall' drupal-console-extend-plugin#18
• Implement the new option on https://github.com/hechoendrupal/drupal-console-core/blob/master/src/Command/Chain/ChainCustomCommand.php
• Update chains that do not require bootstrap https://github.com/hechoendrupal/drupal-console-core/tree/master/config/dist/chain