Add function to work with wall clock time

[scastd]

Describe the feature

In OpenMP, there is a function to get wall clock time in seconds: omp_get_wtime.

A new function could be created that calculates the wall clock times using System.nanoTime(), because it is more precise than System.currentTimeMillis() (StackOverflow reference).

[!NOTE] See [javadoc](https://docs.oracle.com/en/java/javase/21/docs/api/java.base/java/lang/System.html#currentTimeMillis()) for more details about these two functions.

Additional information

• [x] Would you be willing to help implement this feature?

Final checks

• [X] Read the contribution guide.
• [X] Check existing discussions and issues.