Access the METHOD and http Path of the http call in pre-request scripts

Hi! Love this!

I have been porting over some postman collections to http client calls, but I'm missing a bit of functionality. Some of the HMAC signature generating things I've used have needed to get the HTTP method and path from the client call.

Right now the only way I could figure out how to do this is to just type it in the signature bit:

```javascript
const endpoint = "/v1/customer/search?alias=eml"

request.variables.set("endpoint", endpoint)

const payload = request.body.tryGetSubstituted().replace(/\s/g,'')
const signature_content = "POST" +
request.headers.findByName("X-APP-API_TIMESTAMP").tryGetSubstitutedValue() +
request.environment.get("api_key") +
endpoint +
request.headers.findByName("correlation-id").tryGetSubstitutedValue() +
payload

```

What I'd like to do:

```javascript
const payload = request.body.tryGetSubstituted().replace(/\s/g,'')
const signature_content = request.method + //Would give back the http method typed in
request.headers.findByName("X-APP-API_TIMESTAMP").tryGetSubstitutedValue() +
request.environment.get("api_key") +
request.url.path + // would include the query string so like /v1/customer/search?alias=eml (or whatever they typed in excluding the host)
request.headers.findByName("correlation-id").tryGetSubstitutedValue() +
payload
```

Having this would make a generic HMAC library that we could share super easy!

Thanks!