Make it clear that the --profile browser profile argument can be a URL

[benoit74]

While Zimit has support for a --profile to set Browsertrix Browser profile, this parameter can only be a path to a local file.

We should add support for URLs which would be downloaded by zimit before starting the crawler, so that the could be intergrated into the Zimfarm.

Browser profiles are very important to get rid of banners by setting proper cookies before starting the crawler.

@kelson42 I've added the issue to zimit2 project to decide if this should be part of it or not. This should be according to me, it is a small change and a high value.

[benoit74]

This is already supported by browsertrix crawler, just documentation is not clear and I proposed to fix this: webrecorder/browsertrix-crawler#649

[benoit74]

Still need to update usage