Simple Split 2-iter loop: msg_show_console_dialog

Simply spliting the 2-iter loop into code for computing
size of memory & for copying to allocated memory
Add new functions for memory alloction & data copy

From msg_show_console_dialog(), a new function was created
for memory allocation for hotkeys & dialog string.
Similarly, another function created for copying hotkeys
& dialog string.
Style corrections in the two new functions

Style changes in the two new function:
cpy_hotkeys_and_msg() & console_dialog_alloc()
Merge #688 'Refactoring of two-iteration anti-pattern in msg_show_console_dialog()'