Create exchangeable singleton abstraction

[MatthiasKillat]

Brief feature description

Exchangeable singleton abstraction to be used in error handling and logger

1. singleton value exists in static memory
2. lazy construction of value
3. always has a default value (default type can be specified)
4. value can be exchanged with another implementation with a common base class
5. thread-safe

Detailed information

• prototype exists and can be cut out from error handling (it is part of user implementation of the error handling)
• currently used in error handling refactoring to install a different handler at runtime for e.g. tests
• can be used in the logger as well

Note

Separate issue and PR reduces size of error handling PR