Check and report broken hyperlinks

[ArBridgeman]

Summary

In sqlalchemy-exasol, there are already targets for loading & checking links (docs:links & docs:links:check). This should be moved into the toolbox as a common feature. They can be found at:
https://github.com/exasol/sqlalchemy-exasol/blob/master/noxfile.py#L308

It should be evaluated if both should be added as nox tasks or just one and if there is a better task name for them to fit our conventions. If you see something that you'd change about the implementation, feel free to try it out.

Additionally, the equivalent of the docs:links:check should be added to the Documentation job in the checks.yml.

[ckunki]

Many thanks for creating (and working on) this ticket!
See #462 - partially duplicating the current ticket,
but maybe inspiring potential customization options.