Move bson to a normal dependency to prevent issues in yarn

[takameyer]

What, How & Why?

When using yarn as a dependency manager, peerDependencies are not automatically installed. This causes errors with our bson dependency, as many users will not have this package as a direct dependency.
Therefore bson has been removed from the peerDependencies and is now a direct dependency of realm. This has the effect that users can't enforce which version of bson Realm should use, but it's a better compromise than getting runtime crashes where they are forced to add bson as a dependency.

This closes #6040

☑️ ToDos

• 📝 Changelog entry
• 📝 Compatibility label is updated or copied from previous entry
• 📝 Update COMPATIBILITY.md
• 🚦 Tests
• 🔀 Executed flexible sync tests locally if modifying flexible sync
• 📦 Updated internal package version in consuming package.jsons (if updating internal packages)
• 📱 Check the React Native/other sample apps work if necessary
• 📝 Public documentation PR created or is not necessary
• 💥 Breaking label has been applied or is not necessary

If this PR adds or changes public API's:

• typescript definitions file is updated
• jsdoc files updated

[kraenhansen]

Sad that we need to enforce this restriction, but your analysis, conclusion and suggested changes are sound to me 👍