Allow disabling Prometheus scraping config

[aimxhaisse]

When using kubernetes, prometheus config is done by specifying annotations around running containers to tell the prometheus controller of kubernetes how to scrape config. As a result, we need a way in commit boost to just expose /metrics, and leave the rest to Kube.

Currently, we can't disable prometheus' config without crashing:

The application panicked (crashed).                                                                                                     
Message:  failed to load pbs config:                                                                                                    
   0: could not deserialize toml from string                                                                                            
   1: TOML parse error at line 10, column 1                                                                                             
   1:    |                                                                                                                              
   1: 10 | [metrics]                                                                                                                    
   1:    | ^^^^^^^^^                                                                                                                    
   1: missing field `prometheus_config`                                                                                                 
   1:                                                                                                                                   
                                                                                                                                        
Location:                                                                                                                               
   crates/common/src/config/utils.rs:15

[aimxhaisse]

Closing for now as we can bypass commit-boost helper actually for k8s

[aimxhaisse]

It's required to generate the docker-compose file, but it seems it's also required for the PBS module to start (even though it doesn't depend on it directly)

[ltitanb]

fixed in #99