Move all client scripts of mongo nodes (and the shared function) to iife

[Steve-Mcl]

fixes #909

Types of changes

• [x] Bugfix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)

Proposed changes

Prevent global pollution with other nodes that have a global scope oneditprepare function by wrapping this nodes scripts & oneditprepare (shared function) into a single IIFE

Checklist

• [x] I have read the contribution guidelines
• [ ] For non-bugfix PRs, I have discussed this change on the forum/slack team.
• [ ] I have run grunt to verify the unit tests pass
• [ ] I have added suitable unit tests to cover the new/changed functionality