Make the MongoDB connection configurable through GlobalSettings

Description

Changes the way MongoDB is configured so that it pulls its settings from the GlobalSettings instance all other settings are contained in. Maybe there is a way to override @Value and @PropertySource annotations but I spent an hour scouring the Spring documentation and reading blog posts by people who learned English using a Hungarian phrasebook.

Changes

• MongoConfig now uses GlobalSettings
• Default values moved to DefaultGlobalSettingsLoader
  ^{Do you want to come back to my place, bouncy bouncy?}

Additions

None.
^{If I said you had a beautiful body, would you hold it against me? I am no longer infected.}

Test and Review

Documentation will be added when the other settings are also documented, which will happen during the UI upgrade, part of #142 (closed) in milestone %Front-end UI overhaul.
^{Drop your panties, for I can not wait until lunchtime!}

To be filled in by the reviewers

• All of the methods are commented to expectation

• The methods are tested to satisfaction

• There are no unnecessary files present in the MR

• The continuous integration has no problems with the MR

• The MR is filled in as requested (including labels, milestones, and reviewers)

• The documentation is up-to-date

• All nullable parameters are marked as such

^{My nipples explode with delight!}