Rework usage of Krustlet config to allow passing parameters on the command line (#36)

Changed usage of Krustlet config code, so that it does not look at commandline parameters - which allows the agent to use its own parameters.

fixes #34 

Some minor refactoring is contained in here as well:

- Pulled out documentation strings into separate files, which allows editing them as proper adoc files with preview, instead of string literals in Rust code. This makes writing documentation _a lot_ easier.

- Refactored parsing of paths from config into an extra fn and implemented collecting all parse errors before panicing.

Author: soenkeliebau

Cargo.lock

@@ -10,7 +10,6 @@ edition = "2018"
 # We will look to move this to officially released versions as soon as possible
 kubelet = { git="https://github.com/deislabs/krustlet.git", rev="ac218b38ba564de806568e49d9e38aaef9f41537", default-features = true, features= ["derive", "cli"] }
 oci-distribution = { git="https://github.com/deislabs/krustlet.git", rev="ac218b38ba564de806568e49d9e38aaef9f41537"}
-
 k8s-openapi = { version = "0.9", default-features = false, features = ["v1_18"] }
 kube = { version= "0.42", default-features = false, features = ["native-tls"] }
 kube-derive = "0.43"
@@ -30,6 +29,7 @@ thiserror = "1.0"
 url = "2.2"
 pnet = "0.26.0"
 stackable_config = { git = "https://github.com/stackabletech/common.git", branch = "main" }
+hostname = "0.3"
 
 [dev-dependencies]
 indoc = "1.0"