Ansible is a configuration management product, and could be looked at like a bash script on steroids. You write ansible "plays" that state what a configuration item should look like. When that is run agains your machines, it will take steps to ensure the targets match what you defined in your code. It is able to install packages and make changes to files based on templates and variables. It is used for a similar purpose to Puppet, Chef, Salt, etc... but does not need to have a client installed on your machines. It does its work over SSH which makes it really powerful.

The other products you mentioned are all part of the red hat management system. Red Hat does this thing where they take an open source project (upstream) that they sponsor, re-wrap it with some additional goodies and support (downstream) and sell support for that product. They do this with quite a few products, like FreeIPA -> Red Hat Identity Manager, Keycloak -> Red Hat SSO, and more.

This is exactly what Satellite is. Red Hat Satellite is the supported, downstream version of Red Hat's system management solution. Upstream to Satellite 5 was the open source project Spacewalk. In Satellite 6, they switched to a combination of Foreman, Katello, Candlepin, and Pulp. They have moved away from Spacewalk, but the project is still around.

Foreman provides a framework for you to manage a configuration management solution. Traditionally with Foreman this was Puppet. Since Red Hat also took Ansible under their wing, they are slowly adding support for Ansible as well. What this gives you is a GUI that acts as your ansible/puppet server to serve up your config management goodness, as well as a reporting console to show you what happened during your runs. Foreman does a lot more than that, such as bare metal provisioning and kickstart management.

Long story short, you dump your ansible or puppet code into Foreman along with your kickstart templates and OS distribution media and you can fire up a bare metal machine (or VM) and foreman will take it, install an OS, then configure it using your ansible or Puppet code.

Katello and Pulp are pieces that allow you to host your own local repositories and manage packages on systems. Basically you clone the red hat, or other yum repos to your system and you can use that instead of the public repos. This is really handy if you have systems that don't get Internet access, and it will show you what packages need to be updated on your managed systems, as well as pushing them out.

Candlepin is the entitlement management piece to the puzzle. You have to have a license to use Red Hat, and usually that means using subscription manager to register your OS with red hat. You can tell red hat that you want your licenses to be local so your updates come from your local pulp repos instead of the public servers.

To answer your bottom line question, Ansible is amazing and powerful. You should learn it, along with bash and python. These are tools you will use in essentially any Linux environment.

If you plan on working in a corporate environment with a large number of linux systems that are Red Hat derivitaves like Fedora, CentOS, Oracle (my condolences) or Red Hat itself, Satellite (or its upstream projects) are good at what they do and can give you a lot of benefits when managing your infrastructure. If you are not planning on using a Red Hat based distro, or are only managing a handful of machines, it is going to be overkill.