DATABASE: refactor rampdb.tools

[glemaitre]

The current code organisation in rampdb.tools is suboptimal. While it is interested to have query to simplify the code, I think that we should split the api into specific packages. The tools module is also a bit mysterious for the moment.

[kegl]

Can you be more specific pls. I simply collected all scripts querying and writing into the DB into a file. What would be a better way to organize this?

[glemaitre]

You can check the PR.

Basically organize the tools to deal with submission, event, team, user, etc.
So I organized them in different modules.

[kegl]

OK.