Merge configuration files after updating node to 4.5.0 or higher

Bug Description
Users who are updating nodes on MacOS don't get the new configuration because.

This leads to some difficulties as for example, new configuration that comes with 4.5.x contains sections that enables GRPC V2 and if user doesn't replace or adjust old configuration file, GRPC V2 will not be enabled.

Steps to Reproduce
Update node from 4.4 to 4.5.

Expected Result
Configuration should be merged.

Actual Result
Configuration is not merged/overwritten if there already is configurationfile.

Versions

Software Version: 4.4 and 4.5
OS: MacOS specific.

Start by locating the node upgrade and configuration-loading entry points, then reproduce an update from 4.4 to 4.5 on macOS with an existing configuration file. Done means the existing and new configuration are merged or overwritten as intended, including the sections needed to enable GRPC V2.

Written by the indexing model from the issue text.