[GetLogFileUsage] Use local proxy for Exchange commands
[GetLogFileUsage] Refactor Connect-Exchange...

...and add Connect-Server.
[GetLogFileUsage] Refactor Get-LogFolderPath to use proxy exchange commands
[GetLogFileUsage] Refactor retrieving log folder paths
[GetLogFileUsage] Refactor data collection routine
[GetLogFileUsage] Refactor CalcPct