Ld_container path fixes

[SKernchen]

During testing I noticed some things:

1. the "$" is used for the root container and not for current container. If it is intended that way we should think about using the "~" instead.
2. The order feels off, for example:

c1: index=1 path=["$"]

c2: parent=c1 index=2 path=["$", 2] or with index=None und key=None is path ["$","None"] or with index=None ["$", key]

c3: parent=c2 index=3 path=["$", 2, 3]

It feels like you should know which index the root has and rather have a symbol for the current container
3. The Index of the root should be also be displayed.

[led02]

Well, instead of testing it, this might also be just put away. However, some remarks here:

• The path is implemented in the ld_container base class as it is used in other, more generic functionality. However, this leads to the problem, that we need to distinct between "array" and "dict" at the container level - this is a clear compromise of the seperation of concerns principle. Anyways, a container should always only have one, an "index" if it is inside a list or a "key" if it is inside a dict.
• This already gives hints for the next remark: As long as there is no self.parent set, it is not inside anything (which means, it is the root node $) and cannot have an index or a key. However, this is again some problem with seperation of concern as the child nodes need context knowledge.
• Last but not least, the path notation is oriented towards JSON-Path in which $ marks the root while ~ in Unix marks the home directory (which is usually not the tree root).

My opinion would more be like removing the whole path thing but I'm not quite sure about the results of this (and I think it will only break when we start to look at the merging containers).

[SKernchen]

Thank you for clarifying. Yes, I was in the Unix world with user@host:~$ where $ always comes last. So it felt not natural seeing it in front. Whatssoever with the explaination I would keep it that way for now, because it is useful and not too confusing.