Extend BesuConfiguration service

[fab-10]

PR description

This PR adds a method to BesuConfiguration service get the current minGasPrice, in order to implement that a little refactoring was necessary, since services needs to be instantiated very early during the startup, since they need to be visible during the registration of the plugins, but at that stage most configurations are not yet ready, so there is now a separation between the instantiation and the initialization that is done after when the configuration is ready, the initialization is performed before the plugins start, so service are

Fixed Issue(s)

[github-actions]

• I thought about documentation and added the doc-change-required label to this PR if updates are required.
• I thought about the changelog and included a changelog update if required.
• If my PR includes database changes (e.g. KeyValueSegmentIdentifier) I have thought about compatibility and performed forwards and backwards compatibility tests
• I thought about running CI.
• If I did not run CI, I ran as much locally as possible before pushing.