Add a class to the Manage buttons wrapper

[Timo-Breumelhof]

Add CSS class to manage buttons wrapper so it can be styled

Description of PR...

Changes made

• changed https://github.com/DNNCommunity/DNN.Blog/blob/afdeb64a100a804ed2254182b90027d624a0346e/Server/Blog/Controls/ManagementPanel.ascx#L3

PR Template Checklist

• [ ] Fixes Bug
• [x] Feature solution
• [ ] Other

Please mark which issue is solved

Close #209