Doc: FAQ/troubleshooting part for Docker

[Dekabry]

Checking for existing issue

• I have checked for existing issues

Describe the content you'd like to see

Problem

Many docker-using customers reach us for simple docker-related issues and requesting support to assist, usually by sending their docker file.

Examples

Customers encounters issueq with

• chmod
• reaching his app port

Proposal

Add a "frequently encountered issues" / troubleshooting, similar to what the Cellar doc has :
https://developers.clever-cloud.com/doc/addons/cellar/

[juliamrch]

Hi @Dekabry thanks for submitting this issue! I removed Crisp links for confidentiality.

Port configuration already seem specified here : https://developers.clever-cloud.com/doc/applications/docker/#configure-your-docker-application, not sure if doubling the doc is relevant. Maybe make it more visible?

Could you summarize the issue with chmod instead of posting the link here?