New diagrams

[ralphbean]

I added a new application context diagram and deleted the old one. The old one was out of date and just didn't seem helpful to me.

Also, added some text to the book index to provide some context for each of the service links.

Doing this for https://issues.redhat.com/browse/RHTAPSRE-69

[adambkaplan]

Regarding the "Proxy" rectangle - shouldn't this be two shapes?

• Sprayproxy ("Source Webhook Receiver?")
• The CodeReady toolchain ("Kubernetes Proxy", "Workspace Manager"?)

[cmoulliard]

If possible, I would like to suggest some improvements:

• Colorize the boxes to better separate visually the CRD (= API) from Service
• Add dashed vertical lines to show which CRD are managed by which services
• Shade or use a more light color to separate the CRDs that a user can manage (=CRUD) from unmanageable
• Add link under section "Service (Component) Context" about "CodeReady toolchain"
• The Enterprise Contract Service is missing. Is it a mistake ?

@ralphbean