Allow setting params on the command line

When using the command-line interface, you can either specify a list of input URLs and get their browser HTML, or specify a list of JSON object params and run those.

It may be useful to allow the URL list input in combination with a command-line parameter that allows to set parameters that are common to all URLs.

For example:

```
zyte-api urls.txt -p '{"httpResponseBody": true}'
```