Is there a limit on how many folders/sub-folders/sub-sub-folders etc that we can have?  
No, there are no limits on the number of folders or how deep you want to nest them. 

Is there a search function for the Governance Documents?
Yes, located on the top left of the page. Type in a key word and then enter.

What are restricted folders?  
Restricted folders, also known as Board Only folders, are folders for board members only.  Not even administrators/chairs can access a restricted folder (unless they also happen to be a board member).  Restricted Folders are managed by Board Secretaries.