add support for splitting files hierarchically

[earloc]

As a hass.io-admin, I want to optionally split the monolithic confiuration files into small files in a hierarchical way, so that I can better browse and edit the various components in e.g. vs-code more easily.

e.g.:

The following contents of scripts.yaml

some_script_name_1:
  alias: Some.Script.Name 1
  sequence:
  ...
  mode: restart
some_script_name_2:
  alias: Some.Script.Name 2
  sequence:
  ...
  mode: restart
someother_script_name_3:
  alias: SomeOther.Script.Name 2
  sequence:
  ...
  mode: restart

should be exploded/splitted/decomposed into the following folder-structure:

./Scripts/Some/Script/Name 1.partial.yaml
./Scripts/Some/Script/Name 2.partial.yaml
./Scripts/SomeOther/Script/Name 3.partial.yaml

as opposed to the current default-structure:

./Scripts/Some.Script.Name 1.partial.yaml
./Scripts/Some.Script.Name 2.partial.yaml
./Scripts/SomeOther.Script.Name 3.partial.yaml