Create logging functionality

[k-szczech]

Create functions in the graphql backend to enable logging to a log table and retrieving/filtering the logs.
The log creation function can be called from within the backend any time an action is performed to log the relevant information to the database.

Fields logged should be:

• ID (primary key)
• Timestamp (for when an entry was created)
• Event type (administrative, node status change, etc.)
• Node ID (optional, for use with all the node-related events)
• User (optional, for all the user-initiated events)
• Description