Refactor Os::Mutex into CMake Selection

[LeStarch]

F´ Version
Affected Component

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Feature Description

• Refactor Os::Mutex into the Interface, Os::Mutex, and Implementation classes (following pattern of Os::File)
• Implement Posix implementation
• Implement Stub implementation
• Implement Test stub implementation
• Build common rules-based tests
• Build specific posix tests
• Build stub interface tests
• Setup default posix implementation for Posix platforms
• Document