Document behavior with default/custom namespaces

[dmartin35]

If the namespace is created by the user, it will not be deleted.

if a namespace is not specified, a unique namespace will be created, used to create resources in it , and deleted when deleting the chaos experiment

if the user specifies a namespace name, that does not exist, it will be deleted . Bare in mind that the first experiment creating the namespace is owner, and will delete it, event if other experiments are created into that same custom namespace. !!

A default namespace can be used to have all experiments into a single namespace

[dmartin35]

recommandation,

• if you don't care about the namespace, leave the default auto behavior
• if you want all your experiments into a single namespace, create it before ! No experiment will own it , it will last as long as you want to.