Remove ut_legacy.

Removed ut_legacy directory, which contained legacy functions for Neper.
These functions have been moved to Neper's source code.
Add function ut_realloc_1d_ppint.

The function allocates a 1D array of pointers of pointers of integers.
Add function ut_string_array_paste_separator.

This function takes 3 arguments:
- an array of strings
- the qty of strings in the array (or size of the array)
- a char, which will be used as a separator

The function allocates a string, in which it pastes
the strings of the array separated by the provided separator.

The function returns a pointer to the allocated string (char *).