This tool allow to generate a logstash pack of plugin and it is required
by #6168.
This allow the developer to specify which gems it need to be included in
the pack, it will also take care get the parent dependencies.
```ruby
require "paquet"
TARGET_DIRECTORY = File.join(File.dirname(__FILE__), "dependencies")
Paquet::Task.new(TARGET_DIRECTORY) do
pack "manticore"
pack "gemoji"
pack "logstash-output-elasticsearch"
# Ignore some dependencies that the core will provide
ignore "logstash-core-plugin-api"
ignore "logstash-core"
end
```
Fixes#6271
