Define the server startup sequence more precisely

[TheElectronWill]

Current draft

1. Load the global config
2. Initialize the logging framework (cf airframe-log)
3. Start the actor execution service
4. Load the predefined internal IDs in order to enforce their consistency across different runs of the server
5. Register the default server commands
6. Load the global plugin config, which may enable/disable some plugins in some worlds and enforce plugin loading order (the config is above the dependency resolution but must be compatible with it)
7. Open the plugins' jars and resolve the dependencies, ie compute the dependency graph and the correct loading order.
8. Load the plugins: create the instances and call plugin.onLoad()
9. Load the worlds and enable their associated plugins: call plugin.onEnable(World)
10. Start the TCP server