Fixes #36623 - Add buttons and other UX improvements to change content source

[jeremylenz]

What are the changes introduced in this pull request?

Add buttons to the Change Content Source screen so it's less confusing.

When you click either of the buttons, the content source is updated on the Foreman / Satellite server.

In the case of 'Run job invocation', you are then redirected to the job wizard.
In the case of 'Update hosts manually', the following is presented:

Other changes:

• Add a description blurb explaining why you might want to change a content source
• Change 'Environment' to 'Lifecycle environment'. I feel like 'Environment' can mean too many things, and want to start getting away from using it to describe lifecycle environments.

Considerations taken when implementing this change?

What are the testing steps for this pull request?

You should be able to test this without actually setting up multiple content sources.

[theforeman-bot]

Issues: #36623

[jeremylenz]

will rebase once #10667 is merged

[jeremylenz]

@chris1984 rebased

[chris1984]

ACK, works great and nice UI change. Code looks fine, thanks for answering my question.