rewording and clarification of LG-04-03

[gernotstarke]

Reconsider the list of views, and get rid of the hard distinction between UML and non-UML diagrams.
As a first step, reword:

Software architects know at least the following diagrams to describe architectural views:

• UML class, package, component (all R2) and composite-structure diagrams (R3)
• UML deployment diagrams (R2)
• UML sequence and activity diagrams (R2)
• UML state machine diagrams (R3)
• Archimate
• SysML
• C4, see [Brown]
• Entity-relationship diagrams, see [Chen 1976]
• flow charts
• numbered lists
• business-process-modeling-notation (BPMN).

Then reconsider the list.

[gernotstarke]

see #805 as first step.

[gernotstarke]

it wasn't done completely, therefore I re-open it and make a PR.