Add infomation about clearing http cache during uninstallation

## What New Or Updated Would You Like To See?

To update the information about uninstalling Chocolatey CLI, and that there is a HTTP Cache folder that is associated and can be safely deleted as part of the uninstallation.

There are two locations that can be safely deleted if they exist:

- `$env:ProgramData\ChocolateyHttpCache`
- `$env:USERPROFILE\.chocolatey\http-cache`

## Why Is It Needed?

We already documented how Chocolatey CLI is uninstalled, along with some of the variables that are used.
We however are missing the usage of the HTTP Cache directory.

## Additional Context?

There was confusion by one or more users about whether these directories could be safely deleted or not.