Move most references to RealmEntityManagerFactory to use MetaStoreManagerFactory

[collado-mike]

Description

The PolarisEntityManager is almost entirely used as a means to access the PolarisMetaStoreManager and the RealmEntityManagerFactory is really just an alternative to the MetaStoreManagerFactory. In order to narrow dependencies (as described in #417 ), so that components can declare dependency only on the interfaces they need (e.g., PolarisGrantManager or PolarisCredentialVendor), this removes most references to the PolarisEntityManager and uses the PolarisMetaStoreManager directly. This will make declaring dependencies on pluggable components (like authorization grants) easier.

The only piece of logic the PolarisEntityManager actually implements is the construction and preparation of the Resolver, so its getter methods are removed and only the classes that require a Resolver have any dependency on the PolarisEntityManager.

Fixes # (issue)

Type of change

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• Bug fix (non-breaking change which fixes an issue)
• Documentation update
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

Interface-only changes, so all existing unit and integration tests still pass.

Test Configuration:

• Hardware:
• Toolchain:
• SDK:

Checklist:

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• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• If adding new functionality, I have discussed my implementation with the community using the linked GitHub issue

[dennishuo]

Nice refactor! Definitely PolarisEntityManager seems a bit vestigial; once it's more clearly just for assembly of the Resolver with the EntityCache maybe it can be renamed/distilled into a ResolverFactory or something along those lines.