Update and combine Steam related rulesets

[xPaw]

Fixes #15086.

Valve just recently stopped redirecting https to http, as they're preparing for full https roll out. Steam community already forces https.

[Bisaloo]

@xPaw, why did you put ^https? on all rules?

We are trying to get rid of HTTPS->HTTPS rewrites (#10843).

[xPaw]

Because these URLs don't serve correct certificate or content when requested over https. Technically nothing would break if you changed it to ^http as these subdomains are not referenced anywhere directly.

[Bisaloo]

Okay. It would be useful if you could open a follow up PR to fix this.

[dxgldotorg]

Maybe now add a ruleset for store.steampowered.com to circumvent the requirement that users' date of birth be submitted via plaintext http?

[xPaw]

@DXGLdotinfo Does https everywhere rewrite form submissions? Because I have created a rule to redirect the entire subdomain to https.

I wouldn't rush adding other rules because Valve will be further improving their https setup.

[apaloma]

You already have some of these in your rule, but here's the full list of http -> https conversion for Steam's various CDN hosts.

These all become https://steamcdn-a.akamaihd.net/
http://media.steampowered.com/
http://cdn.akamai.steamstatic.com/
http://cdn.edgecast.steamstatic.com/

http://storefront.steampowered.com/v/gfx/ should become https://steamcdn-a.akamaihd.net/steam/

These all become https://steamcommunity-a.akamaihd.net/
http://cdn.steamcommunity.com/
http://community.akamai.steamstatic.com/
http://community.edgecast.steamstatic.com/

These all become https://steamstore-a.akamaihd.net/
http://cdn.store.steampowered.com/
http://store.akamai.steamstatic.com/
http://store.edgecast.steamstatic.com/