Add tags to playbook to allow partial updates

[jasoncorlett]

Add Ansible tags to allow updating only certain parts of the system:

Some possible tags:

• system (yum update ...)
• docker/nimbus (docker, compose, docker-app, nimbusapp)
• user (desktop environment)
• browser (chrome/ff bookmarks)
• script (nimbus-server-update, nimbus-docker-proxy)

The Ansible default is to run all tags.

Sample usage:

# Just the fun stuff
nimbus-server-update --tags "scripts,nimbus"

# Get updated bookmarks
nimbus-server-update --tags browser

# In a hurry, skip system updates
nimbus-server-update --skip-tags system

[jhrabi]

Good call. I like it.