Price Range filter on Vtex legacy PLP

[jovenan]

Feature description

Allows Price Range filter on Vtex legacy ProductListingPage:

By default Vtex sends a JSON like this to loader:

But we can't use this url format in deco, because it returns an error, as it can't handle filters of this type.

In this PR we use the fq=P:[{a} TO {b}] to filter by the range prices registered in the vtex.

[mcandeia]

Looks good, but I would try to remove all uses of regex. Except for certain types of encryption, regex is the second slowest CPU-intensive operation one can perform. I only use regex in cases where it's absolutely necessary, for instance, if you can transform it into startswith/endswith/includes, that would be ideal. Keep in mind that this runs for each request and is CPU-bound. Since Deno is single-threaded, the main thread gets occupied processing regex. And even though it might seem insignificant, when you have hundreds and thousands of simultaneous requests, it ends up making a difference of milliseconds per request.

[jovenan]

@mcandeia Thanks for review. I made these changes.