Update module github.com/PuerkitoBio/purell to v0.1.0

See merge request !4

Configure Renovate

See merge request !1

This is an internal inconsistency that should be investigated.

This allows users of crawl-as-a-library to recover from unexpected
errors as a last resort.

In order to do this we have to plumb it through the queue and the
Handler interface, but it should allow fetches of the resources
associated with a page via the IncludeRelatedScope even if it's behind
a redirect.

Introduce an interface to decouple the Enqueue functionality from the
Crawler implementation.

The whole URLInfo structure, while neat, is unused except for the
purpose of verifying if we have already seen a specific URL.

The presence check is also now limited to Enqueue().

The output stage can now write to size-limited, rotating WARC files
using a user-specified pattern, so that output files are always
unique.

Allow users to add to the exclude regexp lists easily.