Replace Bintray uploading section by Cloud Artifactory

[uilianries]

After Bintray sunset message, we started to remove our connection to Bintray, but our documentation is still strongly connected to Bintray.

As we still have a time transition for Bintray retirement, I would update two point in docs:

1. Add an warning note for Using Bintray and Uploading to Bintray.

2. Add an new section for Artifactory cloud version. We already have an Artifactory section, but it's the standalone version.

[memsharded]

Good point. Please @uilianries do a PR with:

• Remove https://docs.conan.io/en/latest/uploading_packages/bintray/uploading_bintray.html
• Update the info in https://docs.conan.io/en/latest/uploading_packages/remotes.html, removing "Bintray Community Repositories", and adding the FreeTier as an option in "private development"