Introduce get_comment_pages_count() and paginate_comments_links()

[widoz]

Regarding get_comment_pages_count may be a wrapper has_comment_pages so we don't need to make the developer check agains get_comment_pages_count() > 1 everytime.

For paginate_comments_links may be a wrapper would be better so we don't need to add custom configuration.

Or at least, let's just pass the labels such as:

paginate_comments_links(
    esc_html__('Page', 'textdomain'), 
    esc_html__('Previous Comments', 'textdomain'),
    esc_html__('Next Comments', 'textdomain')
)