Modify the configuration management

[manodupont]

The goal would be to change the way the configuration are handled. At the moment a merge system is in place based on NODE_ENV but the system in place doesn't correctly take into account the possible fallback with environment variable. More precisely if NODE_ENV=development and ENV_TEST_XXXXX=titiand in the development.ts file configuration we have
{ test: 'toto' }

but in the parent config we do have
{ test: process.env.ENV_TEST_XXXXX }

we will have test=toto as the final merged configuration.

Describe the solution you'd like
We should refactor this solution by removing all ["development.ts", "production.ts", ...] files and just keep the parent config.ts file to remove any ambiguity or use an already working solution like convict