Clarify how virtual envs can be used in WSGI mode, and ensure we ship the required bits on Windows.

Make-MinGW.bat

@@ -402,7 +402,6 @@ REM Main function Ends
 :CLEANUP_ENV
     ECHO Cleaning up private environment...
     rd "%PGBUILDPATH%\%VIRTUALENV%\Include" /S /Q
-    rd "%PGBUILDPATH%\%VIRTUALENV%\Scripts" /S /Q
     DEL /s "%PGBUILDPATH%\%VIRTUALENV%\pip-selfcheck.json"
 
     ECHO Cleaned up private environment successfully.

Make.bat

@@ -506,7 +506,6 @@ REM Main function Ends
 :CLEANUP_ENV
     ECHO Cleaning up private environment...
     rd "%PGBUILDPATH%\%VIRTUALENV%\Include" /S /Q
-    rd "%PGBUILDPATH%\%VIRTUALENV%\Scripts" /S /Q
     DEL /s "%PGBUILDPATH%\%VIRTUALENV%\pip-selfcheck.json"
 
     ECHO Cleaned up private environment successfully.

docs/en_US/server_deployment.rst

@@ -120,6 +120,17 @@ application may be configured similarly to the example below:
                 Allow from all
         </Directory>
     </VirtualHost>
+
+Now open the file ``C:\Program Files\pgAdmin4\web\pgAdmin4.wsgi`` with your favorite editor and add the code
+below which will activate Python virtual environment when Apache server runs.
+
+.. code-block:: apache
+
+            activate_this = 'C:\Program Files\pgAdmin4\venv\Scripts\activate_this.py'
+            execfile(activate_this, dict(__file__=activate_this))
+
+
+**Note:** The changes made in ``pgAdmin4.wsgi`` file will revert when pgAdmin4 is either upgraded or downgraded.
     
 Apache HTTPD Configuration (Linux/Unix)
 ---------------------------------------
@@ -132,7 +143,7 @@ application may be configured similarly to the example below:
     <VirtualHost *>
         ServerName pgadmin.example.com
 
-        WSGIDaemonProcess pgadmin processes=1 threads=25
+        WSGIDaemonProcess pgadmin processes=1 threads=25 python-home=/path/to/python/virtualenv/
         WSGIScriptAlias / /opt/pgAdmin4/web/pgAdmin4.wsgi
 
         <Directory /opt/pgAdmin4/web>