[Feat]: Allow "News" and "Marketplace" sections to be hidden from the normal users

[martkaczmarek]

Is your feature request related to a problem? Please describe.
In an environment where development work is done by a dedicated admin team and the rest of the company employees are only supposed to use the apps made by the admins, it doesn't make sense for users to have access to "marketplace" and "news" sections, since these are only relevant and useful for the admins.

Describe the solution you'd like
I would like to have an option to hide these entries in the side menu, either with an option in the Settings, or as a new ENV variable.
It could be called something like "Hide Marketplace from the non-admin users".

I don't think it's necessary to deny access to these sections, as users can't create apps if they don't have permissions; just hiding the links is sufficient.

Describe alternatives you've considered
I have tried doing it by some simple CSS rues in the Preload CSS section, but I think it only applies to applications, not the whole web portal.

[FalkWolsky]

We think that these sections already are hidden if you are normal user (no admin, no developer)
Can you check this again? We will also look from our side - but as by our knowledge - this is already the case.
Please re-open if this persist wrong and is an issue for you.

[martkaczmarek]

In my environment the "Marketplace" section is still visible and normal user can access it:

Docker, v2.5.3, ENTERPRISE mode