[Feature] - Health Checker - Public Folder Checks

**Describe the issue**
Check if PF mailbox is not in sync

**Expected behavior**
Report if a PFMBX is not in sync

**Script Output**
PS C:\Users\trudolf> Get-Mailbox -PublicFolder | ft name,*ready

Name   IsHierarchyReady
----   ----------------
PFH                True
PFMBX1            False