Break Figure 13 into three separate context diagrams

[ilkkarinne]

Context diagram in Figure 13 describes three classes: AbstractObserver, AbstractDeployment and AbstractHost while the Figure 14 describes AbstractHost only. This is also noted in Issue 157

To harmonize with the Basic Observation package, I would like to

• Describe only the AbstractObserver in Figure 13
• Add a new context diagram for the AbstactHost as the new Figure 14
• Describe only the AbstractDeployment as the new Figure 15
• Renumber the Figures 15-35 by shifting by one (15->16, 16->17 etc.)

[KathiSchleidt]

Agreed at OMS SWG 27.02.22