dnf-install: add page

[Managor]

• The page(s) are in the correct platform directories: common, linux, osx, windows, sunos, android, etc.
• The page(s) have at most 8 examples.
• The page description(s) have links to documentation or a homepage.
• The page(s) follow the content guidelines.
• The page(s) follow the style guide.
• The PR title conforms to the recommended templates.
• Version of the command being documented (if known):

[tldr-bot]

The build for this PR failed with the following error(s):

pages/linux/dnf-install.md:14: TLDR005 Example descriptions should end in a colon with no trailing characters

Please fix the error(s) and push again.

[dmmqz]

Is in a default option for dnf? The documentation only gives an example if it has been defined as an alias.

[Managor]

I tested in with rocky linux and it worked. I noticed it wasn't directly mentioned under install as a supported alias, but because it worked, I used it in the page. Any reason why the in alias shouldn't be used?

[dmmqz]

The documentation made it sound like the user had to create the alias manually, but if it's provided by default, then that's fine.