Add "Edit" link to Toolbar for admins when viewing individual items on front

[slaFFik]

When you open a single blog post on front you see a handy "Edit" button in Toolbar.
I believe, it will be useful to have such for activity items, forum topics etc. And links will lead to wp-admin area.

Forum topics are harder to think of all UI things, as there is already an edit link (group details etc). So I believe we can start small for activity items only.

[boonebgorges]

Absolutely. Good idea.

[slaFFik]

Attached is a patch, that will add Edit Activity link in Toolbar, when browsing single activity item page on front-end, aka http://trunk.bp/members/michellie/activity/669/

[slaFFik]

Proposing for 2.4 release

[slaFFik]

Screenshot of how it looks on front-end

[slaFFik]

About action to hook:
There is no bp_admin_bar_menu, proposed by @DJPaul. bp_adminbar_menus seems to be deprecated in 2.1 (although it's still used in bp-core-adminbar.php). The core functions also uses admin_bar_menu, so here it is.

Also cleaned up return's.

[imath]

I've refreshed the patch to latest trunk, but i must say 2 things are a bit bothering me:
1/ We are already adding a menu here to manage the member, so BuddyPress will add 2 menus into the WP Admin Bar...
2/ The Existing Edit Links are linking on front-end, this one is bringing us in back end.

[r-a-y]

Thanks for the refresh, imath.

I kind of agree with the first point. It might make sense to make this a real button beside the "Delete" and "Comment" buttons.

The second point doesn't bother me so much because those with 'bp_moderate' only have access.

Since this isn't critical and is easily implemented in a plugin, let's bump this to get more feedback.

[boonebgorges]

I like the extra button. Let's do it.

[boonebgorges]

In 10722:

Add an 'Edit Activity' toolbar link when viewing a single activity.

This button provides better parity with other BP content types (members,
groups).

Props slaFFik, imath.
Fixes #6607.