Settings service

[HugoDelval]

This PR:

• Update the Dockerfile to ease the development process by moving the ADD statement after all the dependencies installation
• Exposes a new endpoint (/ips_handled/) which lists the IPs handled by the AS
• Introduce the concept of a Settings service, which provides secrets from a factory. This way you can easily implement a new way to fetch the application secrets, for example by using Vault

[coveralls]

Coverage increased (+0.3%) to 64.136% when pulling 2d3ae0f on HugoDelval:settings-service into 31b3d5c on ovh:devel.

[coveralls]

Coverage increased (+0.5%) to 64.345% when pulling 2a5fde3 on HugoDelval:settings-service into 31b3d5c on ovh:devel.

[coveralls]

Coverage increased (+0.5%) to 64.345% when pulling 9127c08 on HugoDelval:settings-service into 31b3d5c on ovh:devel.

[coveralls]

Coverage increased (+0.3%) to 64.161% when pulling 1528500 on HugoDelval:settings-service into 31b3d5c on ovh:devel.

[coveralls]

Coverage increased (+0.3%) to 64.161% when pulling 0e8cfbd on HugoDelval:settings-service into 31b3d5c on ovh:devel.

[coveralls]

Coverage increased (+0.3%) to 64.211% when pulling 7353f44 on HugoDelval:settings-service into 31b3d5c on ovh:devel.