Common: add list of common tickets

[chuwy]

We create a lot of tickets at Snowplow that share implementation across the projects.

Examples:

• Bump X to Y
• Add X credentials to travis.yml
• Remove vagrant setup
• Change Travis distribution to Trusty
• Use sbt-scalafmt
• Replace scalaz by cats
• Replace scopt by decline
• Everything related to CI/CD
  etc

In order to make implementations consistent and discoverable we can have a short-list of common tickets.

Lately we created many tickets (for dockerizing apps) that technically do the same thing, but have different implementations, because implementers couldn't find original tickets.