"Upload VCL" button should default to no change

The current implementation of the "Upload VCL" button on /admin/config/services/fastly/vcl appears to upload all the VCL files in the vcl_snippets folder to Fastly and adds them to the live VCL configuration file for your site.

Problems:

1. The entire documentation for the button is: "Upload Fastly VCL snippets that improve cacheability of the site. Not required but highly recommended." It doesn't explain what VCL snippets might be uploaded. I read this to mean that I needed to click the button to enable a system for uploading snippets. Nope! It went ahead and uploaded three VCL snippet files, changing my live Fastly configuration. There's no confirmation about what it did, either -- no indication that the VCL configuration on Fastly has changed.

2. The snippets in vcl_snippets are super-useful, but they aren't appropriate for all Drupal implementation. For example, if you use private files and a CDN, one of the snippets breaks serving private static files. The default behavior of a poorly-documented button shouldn't make changes that aren't universally a good idea.

3. It's not clear what the "Activate version" checkbox does.

Suggestions:

1. Add instructions to /admin/config/services/fastly/vcl. How about something like this: "Upload VCL snippets and automatically add them to your Fastly VCL configuration file. BEFORE clicking this button, review the files in the vcl_snippets directory (part of the Fastly module code) to make sure they apply to your Drupal configuration. Remove any files you don't want added to your Fastly configuration. See the vcl_snippets/README.txt file for more information."

2. Make the default behavior of the button to NOTHING. Create three subdirectories of the vcl_snippets directory named "to_upload", "uploaded", and "examples". Move the existing VCL snippets into the "examples" directory so the "to_upload" directory is empty. Change the button to upload files from the "to_upload" directory and them move them to the "uploaded" directory so they don't get uploaded and appended again. If you make this change, change the suggested instructions in #1 to match (replace "vcl_snippets" with "vcl_snippets/to_upload").

3. Consider adding more information to that README.txt file. (What does "In addition to these snippets you need to add a request setting" mean? Where is this setting?)

4. When you click the "Upload VCL" button, display the list of filenames to be uploaded and ask for confirmation.

5. Provide an explanation for what the "Activate version" checkbox does.