Problem installing Knowledge base module
The install yml is not in the wrong place.  This is a new module with 1 install currently in beta state so you might face a few problems with it if not all bugs are not ironed out but perhaps this is not the case.

The error message is not that helpful I must admit. If you want to see what dependencies you are missing you go into the .info.yml file and can also be seen online here and here is the relevant section

...
dependencies:
  - drupal:field
  - drupal:file
  - drupal:text
  - drupal:node
  - drupal:group
  - drupal:gnode
  - drupal:views
  - drupal:views_jump_menu
  - drupal:eva


for field, file, text, node, views are part of core (nothing to do)

but you have to download 
https://www.drupal.org/project/group (for group and gnode)
https://www.drupal.org/project/views_jump_menu 
https://www.drupal.org/project/eva

before you are able to install this module

I suggest that you start looking into installing things using composer that takes care of the dependencies for you so if you did 

composer require drupal/kb 


all the dependencies would also be installed for you

More info about composer based drupal installations can be found here and here and perhaps other places but those are good starting points