Fix Model READMEs

[frenchja]

Models

Add individual model README with explicit instructions, adapting https://github.com/syberia/examples/blob/master/models/README.md.

• [ ] https://github.com/syberia/examples/tree/master/models/dev/titanic
• [ ] https://github.com/syberia/examples/tree/master/models/dev/survey
• [ ] https://github.com/syberia/examples/tree/master/models/dev/uci