inventory and python-inventoryclient: remove the recipes

inventory and python-inventoryclient: remove the recipes

inventory and python-inventoryclient has been revomed
from upstream:

```````````````````````````````````````````````
commit d59ba5fdc21a89581cdc4e3fad038645b9d20754
Author: Al Bailey <Al.Bailey@windriver.com>
Date:   Tue Jan 7 08:41:36 2020 -0600

    Remove unused inventory and python-inventoryclient

    Neither of these components were maintained or used, and so are
    being abandoned.

     - inventory was an old fork of the sysinv code
     - python-inventoryclient was an old fork of the cgts-client code

    The devstack commands, although currently disabled, have also
    been updated.

    Story: 2004515
    Task: 37538
    Depends-On: https://review.opendev.org/701591
    Signed-off-by: Al Bailey <Al.Bailey@windriver.com>
```````````````````````````````````````````````

Issue-ID: INF-215

Signed-off-by: Jackie Huang <jackie.huang@windriver.com>
Change-Id: I84c27f2963b190b5e7340aa6cb4ae1c36130ea9e