Create action "bbp_template_before_topic_loop"

[aravoth]

There is a bbp_template_after_topic_loop which allows us to place elements below the topic loop when using show_lead_topic, but there is nothing that allows you to do the same thing above it. If a person is using show_lead_topic as an alternate display, the only real option is to place the element before the replies loop, which actually makes the element display twice. I'm placing this ticket to request that a new action be made to better accommodate the show_lead_topic layout.

[johnjamesjacoby]

(In [3690]) Tweak new template action names in content-single-topic-lead.php. Fixes #1724.