New File Watcher logic, to run logic on file events

[Badgerati]

Use Register-ObjectEvent on FileSystemWatcher objects, but do the register in a new runspace - and we only need 1 runspace as well, multiple won't work here.

Need to make sure the FileSystemWatchers are all disposed on server restart and stop.

Add-PodeFileWatcher `
    -Name <string> `
    -Path '<directory>' `
    -ScriptBlock {} `
    [-FilePath <string>] `
    [-ArgumentList @()] `
    [-EventName @('Changed', 'Created', 'Deleted', 'Renamed' | *)] `
    [-NotifyFilter @([System.IO.NotifyFilters]'FileName,DirectoryName,LastWrite,CreationTime')] `
    [-Include '*.*'] `
    [-Exclude @()] `
    [-NoSubdirectories]

• The 'Error' event is monitored, but is done internal within Pode
• Default events are Changed, Created, Deleted, and Renamed (ie: *)
• Default NotifyFilters are FileName, DirectoryName, LastWrite, CreationTime
• Functions also for: Test, Get, Remove, Clear, Use

Scriptblock parameters:

-ScriptBlock {
    param($args0, ..., $argsX)

    $FileEvent = @{
        Type = <Changed, Created, Deleted, Renamed>
        FullPath = <FullPath>
        Name = <Name>

        # if Renamed event type
        Old = @{
            FullPath = <FullPath>
            Name = <Name>
        }

        DateTime = <Now>
        Etc.
    }
}

Example, to watch a C:\temp folder and all *.txt files - for changed events only:

Add-PodeFileWatcher -Path 'C:\temp' -Include '*.txt' -ScriptBlock {
    "[$($FileEvent.Type)]: $($FileEvent.Name)" | Out-Default
}

We could also support :parameter placeholders in wildcard paths. For example: C:/Websites/:website would monitor files changes at C:/Websites/*, and the "website" parameter would be the name of the site available at $FileEvent.Parameters['website'] - similar to Routes.