[Desktop] Support denyallow adblock rules

[antonok-edm]

uBlock Origin introduced the denyallow option for network filters in 1.25.3b4, as noted in the static filter syntax documentation.

The purpose of denyallow is bring default-deny/allow-exceptionally ability into static network filtering arsenal.

Example:

*$3p,script,denyallow=x.com|y.com,domain=a.com|b.com

The above filter tells the network filtering engine that when the context is a.com or b.com, block all 3rd-party scripts except those from x.com and y.com.

Essentially, the new denyallow option makes it easier to implement default-deny/allow-exceptionally in static filter lists, whereas before this had to be done with unwieldy regular expressions[1], or through the mix of broadly blocking filters along with exception filters[2].

[1] hg.adblockplus.org/ruadlist/rev/f362910bc9a0

[2] Typically filters which pattern are of the form |http*://

As of the time of this issue this syntax is already used in at least one rule at https://github.com/uBlockOrigin/uAssets/blob/3607fd8adf53104fc22c84c52dc495fb74b41864/filters/filters-2020.txt#L2410:
*$3p,script,domain=boards.4channel.org,denyallow=4cdn.org|4chan.org|google.com|gstatic.com|cdn.mathjax.org|cdnjs.cloudflare.com|hcaptcha.com