deprecate readthedocs.io

[AaronK]

We still have a few references to readthedocs.io . Remove them and point to docs.intelmq.org

aaron@host:~/git/certtools/intelmq$ grep -r readthedocs.io .
./intelmq/bots/collectors/twitter/collector_twitter.py:To get api login data see: https://python-twitter.readthedocs.io/en/latest/getting_started.html
./intelmq/bots/parsers/generic/parser_csv.py:DOCS = "https://intelmq.readthedocs.io/en/latest/guides/Bots.html#generic-csv-parser"
./intelmq/lib/bot.py:                                  'https://intelmq.readthedocs.io/en/latest/user/FAQ.html'
./intelmq/lib/bot.py:        see https://intelmq.readthedocs.io/en/develop/dev/library.html
./intelmq/lib/utils.py:        see: https://dnspython.readthedocs.io/en/stable/resolver-class.html#dns.resolver.Resolver.resolve
./intelmq/etc/feeds.yaml:      documentation: https://n6.readthedocs.io/usage/streamapi/
./intelmq/bin/intelmqctl.py:                                         "https://intelmq.readthedocs.io/en/maintenance/user/FAQ.html"
./NEWS.md:See the [Shadowserver Reports API bot's documentation](https://intelmq.readthedocs.io/en/latest/user/bots.html#shadowserver-reports-api).
./NEWS.md:The [Data format documentation](https://intelmq.readthedocs.io/en/maintenance/dev/data-format.html#rules-for-keys) describes the required format.
./NEWS.md:The [sieve bot documentation](https://intelmq.readthedocs.io/en/maintenance/user/bots.html#intelmq-bots-experts-sieve-expert) has been updated to reflect on these new changes.
./NEWS.md:The [Shadowserver Parser Bot documentation](https://intelmq.readthedocs.io/en/maintenance/user/bots.html#shadowserver-supported-reports) lists the supported feeds, as well as the legacy feeds.
./NEWS.md:The documentation is now available at [intelmq.readthedocs.io](https://intelmq.readthedocs.io/).
./NEWS.md:The Shadowserver Collector is now able to collect data from the [Shadowserver Reports API](https://intelmq.readthedocs.io/en/maintenance/user/bots.html#shadowserver-reports-api). Moreover the Shadowserver Parser now supports the JSON format used by the Reports API.
./NEWS.md:More details can be found in our [documentation](https://intelmq.readthedocs.io/en/maintenance/user/bots.html#sieve).
./NEWS.md:Now you're able to fetch data from Kafka with the [Kafka Collector](https://intelmq.readthedocs.io/en/maintenance/user/bots.html#kafka).
./NEWS.md:`IntelMQ-Manager` PHP backend is getting replaced by the newly developed `IntelMQ-API`. The `IntelMQ-Manager` release only contains the files for the web frontend. The `IntelMQ-Manager` packages now depend or recommend the installation of the `IntelMQ-API` package, therefore a normal upgrade should pull in the API. Follow the instructions in our [documentation](https://intelmq.readthedocs.io/en/maintenance/user/intelmq-api.html) to configure the API. It uses its own authentication backend now, how to setup users is described in the [documentation](https://intelmq.readthedocs.io/en/maintenance/user/intelmq-api.html#adding-a-user).
./docs/dev/adding-feeds.md:    - [Shodan search API](https://shodan.readthedocs.io/en/latest/tutorial.html#searching-shodan)
./docs/user/bots.md:also <https://requests.readthedocs.io/en/master/user/advanced/#timeouts>. Defaults to 30.
./docs/user/feeds.md:**Documentation:** <https://n6.readthedocs.io/usage/streamapi/>
./docs/admin/integrations/n6.md:- n6 documentation: [n6.readthedocs.io](https://n6.readthedocs.io/)
./intelmq.egg-info/PKG-INFO:Project-URL: Documentation, https://intelmq.readthedocs.io/
./intelmq.egg-info/PKG-INFO:        IntelMQ's documentation is available at `intelmq.readthedocs.io <https://intelmq.readthedocs.io/>`_.
./intelmq.egg-info/PKG-INFO:        More tools can be found in the `Ecosystem chapter in the documentation <https://intelmq.readthedocs.io/en/latest/user/ecosystem.html>`_.
./intelmq.egg-info/PKG-INFO:        - Have a look at our `Developers Guide <https://intelmq.readthedocs.io/en/latest/dev/guide.html>`_ for documentation.
./setup.py:        'Documentation': 'https://intelmq.readthedocs.io/',
./CHANGELOG.md:  - The documentation is now available at https://intelmq.readthedocs.io/en/latest/
./.github/pull_request_template.md:Make sure you follow the instructions in the [Developer Guide](https://intelmq.readthedocs.io/en/latest/dev/guide.html) - it describes how to run the test suite and which coding rules to follow.
./contrib/eventdb/README.md:- SQL queries to set up a separate `raws` table, described in https://intelmq.readthedocs.io/en/latest/user/eventdb.html#separating-raw-values-in-postgresql-using-view-and-trigger