Remove dependency on Parse JS SDK

[mtrezza]

New Feature / Enhancement Checklist

• [x] I am not disclosing a vulnerability.
• [x] I am not just asking a question.
• [x] I have searched through existing issues.

Current Limitation

Parse Server currently depends on the Parse JS SDK. This is because the Parse JS SDK is leading a double life - as a Parse client SDK and as a internal module of Parse Server that is uses for various features. This creates the following issues:

• Difficult development; its adds a circular dependency where changes in the server requires changes in the SDK and vice versa.
• Bloated client SDK; it contains code that is unnecessary outside of the Cloud Code environment.

Feature / Enhancement Description

Remove Parse Server's dependency on the Parse JS SDK. It should only be needed:

• As a dependency alongside Parse Server if a developer wants to use the Cloud Code feature. In that case the developer needs to add the Parse JS SDK as a dependency themselves.
• As a devDependency for the Parse Server tests of Cloud Code.

All elements of the Parse JS SDK that are currently in use in Parse Server should be moved to the Parse.Cloud namespace.

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