4500: RFP UA spoof stuff

Cleaning up the UA spoof stuff in the sticky, as a ticket was just closed (52 is now a temporary hard-coded value: 1418672 - I guess they're running out of time), so also cleaning up the info, and consistent layout

Two issues: The code to determine the ESR number is out of whack (by one) since the next ESR is 60. 59 stable is almost here. So they have decided to hard-code the value as 52, for now. The second issue is that Aurora/Nightly are ahead of stable/ESR and can thus unmask themselves as Aurora/Nightly. The hard-coded value for now also solves this.

If you follow the sticky for RFP, you will see there is a ticket for using the update channel information (eg stable, beta, dev, nightly etc) to determine when and how calculate the version spoof in future, and they'll also rejig the numbering algorithm to account for ESR being out by one. These are tickets https://bugzilla.mozilla.org/show_bug.cgi?id=1418162 and https://bugzilla.mozilla.org/show_bug.cgi?id=1428111

user.js

@@ -1552,10 +1552,10 @@ user_pref("privacy.firstparty.isolate.restrict_opener_access", true);
       This spoof *shouldn't* affect core chrome/Firefox performance
  ** 1217238 - reduce precision of time exposed by javascript (FF55+)
  ** 1369303 - spoof/disable performance API (see 2410-deprecated, 4602, 4603) (FF56+)
- ** 1333651 & 1383495 & 1396468 & 1393283 & 1404608 - spoof Navigator API (see section 4700) (FF56+)
+ ** 1333651 & 1383495 & 1396468 - spoof Navigator API (see section 4700) (FF56+)
       FF56: The version number will be rounded down to the nearest multiple of 10
-      FF57: The version number will match current ESR
-      FF59: The OS will be reported as Windows, OSX, Android, or Linux (to reduce breakage)
+      FF57: The version number will match current ESR (1393283, 1418672)
+      FF59: The OS will be reported as Windows, OSX, Android, or Linux (to reduce breakage) (1404608)
  ** 1369319 - disable device sensor API (see 4604) (FF56+)
  ** 1369357 - disable site specific zoom (see 4605) (FF56+)
  ** 1337161 - hide gamepads from content (see 4606) (FF56+)