Update /conf file structure

[amandakys]

We want to update the new /conf folder structure to look like

├── conf
    └── base
	├── catalog_{pipeline-name}.yml          #blank files
	└── parameters_{pipeline-name}.yml       #blank files
        ├── catalog.yml          #blank files   
	└── parameters.yml       #blank files

with separate catalog and parameters files for each pipeline in the project

rather than

├── conf
    └── base
        └── parameters.yml          
	    ├── {pipeline-name}.yml     #blank files
        ├── catalog.yml              #blank files   
	└── parameters.yml           #blank files

This change needs to be reflected in the

• kedro pipeline create command Update kedro pipeline create to use new /conf file structure  #2752
• the starters Update starters to use new /conf structure  #2753
• the docs Update docs to reflect change to /conf file structure  #2754

[yetudada]

Add the docs ticket to this: #2754

[merelcht]

This has been completed in:

• Update kedro pipeline create to use new /conf file structure #2856
• Update starters to use new /conf structure kedro-starters#141
• update docs to reflect change to /conf file structure #2913