Installing ipykernel requires admin on Windows

[rchiodo]

Steps to repro:

1. Create venv
2. Switch to it
3. Switch on raw kernel support
4. Run interactive window
5. Follow install prompts
6. Expect kernel to start

Kernel actually fails with an import dll load failure when importing the win32api package.

This is because the installer for pywin32 needs admin rights.

[rchiodo]

Need to repro with jupyter first to see if this happens with jupyter too.

[rchiodo]

Okay this is a result of either;

• Using anaconda's python in a virtual environment (not supported)
  or
• Using windows store version 3.7 or earlier.

we should detect these two conditions and say they aren't supported.

[DonJayamanne]

This should already be fixed for the following scenario
Using windows store version 3.7 or earlier.

[DonJayamanne]

Testing
See the comments right on top (contains steps for repro #1253 (comment))