Refactor Privilege checks for Patterns

[mhinkie]

Is your feature request related to a problem? Please describe.
In ba-meyer-master role and privilege management was introduced for Pattern Candidates and Issues. The checks for global privileges were also introduced for patterns but resource specific privileges are not finished for patterns.

Describe the solution you'd like
Check for resource specific (i.e. pattern-specific) privileges when deciding if editing of a particular pattern is enabled or not in the UI.
Also ensure references privilege names are always taken from src/app/core/user-management/_models/privilege.enum.ts