Add Sonatype Nexus remote repository support

[Nantero1]

Sonatype Nexus is a famous and widely used repository manager used to securely store packages and has an excellent user access control.

Usually it is used to host R, Java, Python and other build artifacts. Nevertheless, its hosted RAW repository type allows it to store any files and data!
It would be nice to add this famous, tested and flexible artifactory as a remote storage type to DVC and be able store ML data.

[Nantero1]

@efiop Privet Ruslan 👍 I reaaaaally like DVC! Thanks for this tool!
This feature-request is not just wishful thinking, I actually implemented this already- I'm running all pre-commit hooks to make a Pull request with this feature included. Please give me some more minutes 🚀

Was not expecting someone to react so quickly 😄

[efiop]

Hi @BenLinnik !

Please note that we are migrating to fsspec #5162 and there are a few remote PRs pending already for other clouds (e.g. osf, dropbox, etc). We will not be merging new implementations unless they comply with fsspec. At the same time it is becoming harder and harder for dvc team to maintain quality support for the variety of clouds on our own, so the absolute best way to go about it would be for you to follow fsspec and maintain your implementation (e.g. how s3fs does it) in your own package (and also maybe try to get it accepted into https://github.com/intake/filesystem_spec/tree/master/fsspec/implementations). That way it will be really easy for us to accept it, or, if our plugin mechanism will be ready by that time, just use your implementation automatically through fsspec registry or some explicit option.

[Nantero1]

Oh ok, this is new to me. I will have a look into it. Please keep up the good work!

[efiop]

@BenLinnik Thank you! 🙏 And sorry for making you now adapt your PR again, we are in the middle of migrating ourselves, so there is a mixup in the code 🙁 We'll document it properly in the contribution guide after the 2.0 release. Thanks again for contributing!

[efiop]

Doesn't seem like there is much demand for this at all. Closing.