Support $replace

[seia-soto]

continues #3885

[seia-soto]

Noticed that the overall html filter capability should be improved to support this feature on Ghostery adblocker library. If possible, I want to extend the full html filtering capability. The implementation detail may change heavily based on the direction of this feature. For example, the current html filtering capability is limited at ^script:has-text.

One more thing to think is that our html filtering capability lives at the cosmetic filter. However, $replace modifier should live in the network filter.