feat(core): Add experimental DomainBasedErrorsFilter integration

[chargome]

This PR introduces an experimental domain-based error filter that copies parts of the existing thirdPartyIntegration, but without the need to run an applicationkey through a bundler first.

• Allows filtering or tagging errors based on whether they contain third-party stack frames.
• Allows setting an is_external flag on stackframes.

I put all of this into a separate integration to test it on docs, but ultimately (if successful) I'd refactor this into thirdPartyIntegration and eventFilters respectively.