CP Move Timer class from RealTime Solution

[mpostol]

Describe problem

Move Timer and appropriate UT classes from RealTime Solution

Describe the solution you'd like

It must be harmonized with the current .NET and refactored to meet education purposes.

List of tasks to be accomplished

• Move the Timer as is
• Move the TimerTest as is
• Improve both to meet the repository and current knowledge requirements, for example, instead of sealed it should be a static class

[mpostol]

Contributes to #427