[+] Add a initial content pack settings

[sahya]

Hi, there.

I noticed a lack of configuration in templates/graylog.server.conf.j2. So I propose this configuration when I referenced [git.codificar.com.br/diogo.coutinho] this config

Detail; The add settings are not contained the template of graylog.server.conf.j2 whether contained the default config parameter defaults/main.yml#L120-L123

Notes for Reviewers

• [ ] The commit history must be preserved - please use the rebase-merge or standard merge option instead of squash-merge
• [ ] Sync up with the author before merging

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