Grav comment classes

[juekr]

Added the possibility to add classes to comment section elements. The classes for wrapper, table, rows, columns, meta information and alert area are configured via config .yaml like this:

classes: wrapper: comments-wrapper table: table-comments rows: tr-comments cols: td-comments meta: comment-meta alert: comment-alert

If left empty, they default to class="" – except for the alert (this defaults to class="alert").

Also added an id to the outer wrapper class that is added as target to the form's action (so user land directly in the comment section after submitting).