refactor lorem Data

[krupalbhat]

This modification is done in reference to #569.

[krupalbhat]

Hey, I will fix the tests and push. I didn't notice the changes in the CMake file, so in my system, tests were not built

[krupalbhat]

In the lorem.cpp file:

• I have changed the word() function to return string_view.

• In other functions like words() and sentence(), a vector of string is created because the StringHelper::join() function expects std::vector<std::string> as a parameter. Since my modifications the word() function returns string_view, I am converting these string_views to strings in order to add them to the vector.

• I was thinking we could create a vector of string_view and add another overloaded StringHelper::join() function that takes a vector of string_view as an argument. This function will join string_views to form string.

What do you think about this?

[cieslarmichal]

Good idea with overlosding, we can implement it :)