Move configuration form into Services menu [#3364447]

Problem/Motivation

The configuration page is currently in the "System" configuration menu, which is wrong and should be "Services" instead.
For large projects this is confusing with menu configuration items.

Please move it over :)

Steps to reproduce

Proposed resolution

Remaining tasks

User interface changes

API changes

Data model changes

Issue fork rest_api_access_token-3364447

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3364447-fix-menu-item-parent changes, plain diff MR !4
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