[#739] Delete unnecessary `HasStorage` constraints

Description

A Lorentz.Contract has:

• a NiceStorage constraint, which implies a HasAnnotation st constraint.
• a NiceParameterFull constraint, which implies a ParameterDeclaresEntrypoints constraint.

However, HasAnnotation st and ParameterDeclaresEntrypoints aren't always needed.

When a lorentz contract is imported from a file, the annotations are extracted from the .tz file.

This means that functions like importContract and embedContract require the user to declare HasAnnotation and ParameterDeclaresEntrypoints instances, even though they're ignored and never used.

This MR aims to remove these constraints, and use them only where they're actually needed.

Related issue(s)

Resolves #739 (closed)

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