Update entry processor to allow blocking/keeping articles by tags

[filipedeluna]

Since tags are supported and parsed, and contain valuable metadata, it makes sense that our filtering rules also apply to them.

Use case:

• I personally subscribe to a news feed that spams me with soccer news I couldn´t care less about. This change allows me to ignore all of them easily.

Do you follow the guidelines?

• I have tested my changes
• I read this document: https://miniflux.app/faq.html#pull-request

[fguillot]

There is some linter issue detected: https://github.com/miniflux/v2/pull/2269/files#diff-b77c1e5ef2b613c406def0c38849f547a4d7636e21d25b2441f6eced4c5cbc70R120

[filipedeluna]

There is some linter issue detected: https://github.com/miniflux/v2/pull/2269/files#diff-b77c1e5ef2b613c406def0c38849f547a4d7636e21d25b2441f6eced4c5cbc70R120

Oopsie poopsie :(

Thanks!

[x0tester0x]

Please update the documentation on how you can use this.
Thanks