Add Reverse Proxy IPs for Cloudflare and AWS CloudFront programmatically

[benjaminpick]

Is your feature request related to a problem / specific use-case? Please describe.

As it is quite difficult to specify the reverse proxy for cloud providers, they should be handled by the plugin, at least the big ones.
Here are the list of IPs to whitelist:

Cloudflare:

• https://www.cloudflare.com/ips-v4
• https://www.cloudflare.com/ips-v6
• Doc See https://www.cloudflare.com/ips/

AWS Cloudfront:

• https://ip-ranges.amazonaws.com/ip-ranges.json
• Doc see https://forums.aws.amazon.com/ann.jspa?annID=2051

ToDos:

• In both cases, internal IPs should always be whitelisted Reverse Proxy: Whitelist internal IPs by default #172
• Get Ips
• Store / Retrieve DB
• Implement daily updates of the IP lists
• UI: Enable Whitelist for these providers