Add make.ps1 cmdlet + activateenv command for Windows make scripts (#4087)

* Add missing command to `make.bat`'s help

* Add `activateenv` and `deactivateenv` commands to `make.bat`

* Add help to `Makefile`

* Add `make.ps1` cmdlet

make.ps1

@@ -0,0 +1,89 @@
+<#
+.Synopsis
+Makefile script in PowerShell that contains commands useful during development for Red.
+
+.Description
+Available commands:
+   reformat                   Reformat all .py files being tracked by git.
+   stylecheck                 Check which tracked .py files need reformatting.
+   stylediff                  Show the post-reformat diff of the tracked .py files
+                              without modifying them.
+   newenv                     Create or replace this project's virtual environment.
+   syncenv                    Sync this project's virtual environment to Red's latest
+                              dependencies.
+   activateenv                Activates project's virtual environment.
+
+.Parameter Command
+Command to execute. See Cmdlet's description for more information.
+
+#>
+
+# I'm too dumb for PowerShell, so $script:availableCommands needs to be defined in 2 places // Jack
+
+[CmdletBinding()]
+param (
+    [Parameter(Mandatory=$false)]
+    [ArgumentCompleter({
+        param (
+            $commandName,
+            $parameterName,
+            $wordToComplete,
+            $commandAst,
+            $fakeBoundParameters
+        )
+        $script:availableCommands = @("reformat", "stylecheck", "stylediff", "newenv", "syncenv", "activateenv")
+        return $script:availableCommands | Where-Object { $_ -like "$wordToComplete*" }
+    })]
+    [String]
+    $command,
+    [switch]
+    $help = $false
+)
+
+function reformat() {
+    black $PSScriptRoot
+}
+
+function stylecheck() {
+    black --check $PSScriptRoot
+}
+
+function stylediff() {
+    black --check --diff $PSScriptRoot
+}
+
+function newenv() {
+    py -3.8 -m venv --clear .venv
+    .\.venv\Scripts\python.exe -m pip install -U pip setuptools
+    syncenv
+}
+
+function syncenv() {
+    .\.venv\Scripts\python.exe -m pip install -Ur .\tools\dev-requirements.txt
+}
+
+function activateenv() {
+    .\.venv\Scripts\Activate.ps1
+}
+
+$script:availableCommands = @("reformat", "stylecheck", "stylediff", "newenv", "syncenv", "activateenv")
+
+if ($help -or !$command) {
+    Get-Help $MyInvocation.InvocationName
+    exit
+}
+
+switch ($command) {
+    {$script:availableCommands -contains $_} {
+        & $command
+        break
+    }
+    default {
+        Write-Host (
+            """$command"" is not a valid command.",
+            "To see available commands, type: ""$($MyInvocation.InvocationName) -help"""
+        )
+        break
+    }
+}
+