Convert the number field to be configurable

The points field added in this patch is still non-configurable on /admin/structure/point_type/default/edit/fields

Attached screenshot shows what we want to achieve here. We want the site builder to be able to edit he points field settings, but not to delete it.

Below is the conversion I had with @berdir, which offers a solution to #6:

<skyred> berdir: ping
8:01 PM <berdir> skyred: pong
8:03 PM <skyred> berdir: I am porting Userspoints to Points in a sandbox project. Running int a road block, in D8, how can I programmatically add a base/default field to all Point Entity bundles, including the ones added by site admin, also I need this field to be configurable, but not delete-able. Like this screenshot: https://www.drupal.org/files/issues/Manage%20fields%20%7C%20Payment.png
8:03 PM <skyred> berdir: the example on the screenshot was done via config/install, which only works for existing bundle.
8:04 PM <berdir> skyred: why does it need to be always there but configurable?
8:11 PM <berdir> skyred: what you can do is the same node does with the body field. provide a non-deletable field storage default config, add the field when new bundles are created. use entity access th prevent deletion
8:13 PM <skyred> berdir: I am trying to add the core number field to every Point Entity bundle. I'd like it to be configurable, so the site admin can control the validation and precision. But, it cannot be deleted, so the rest of the module  can depend on it
8:14 PM <berdir> skyred: you could also have configuration that you use in a base field, that's better in terms of storage as it is then in the base table. it's not something that can be changed as soon as you have configuration anyway and they are storage settings, so can't be different per bundle either

Below is the same question I asked @bojanz, and his reply:

<skyred> bojanz: I am trying to add a locked field to a custom entity just like commerce did. But, I am using hook_entity_base_field_info() instead of config/install, but this way, I cannot see the fields on the custom entity/bundle/edit page, I can only see the fields on the form display and manage display page. Do you know a good example that I can look? 
6:23 PM <bojanz> skyred: commerce_shipping uses the same method to add store fields
7:05 PM <skyred> bojanz: I just looked at "/admin/commerce/config/store-types/online/edit/fields", the "Supported shipping countries" does not show. This is same on my project, too. Is this a bug? or by design
7:26 PM <bojanz> skyred: by design, that listing only shows configurable fields
7:27 PM <bojanz> skyred: you canćt edit a base field, it comes from code
7:48 PM <skyred> bojanz: the entity api docs says hook_entity_base_field_info produces a "configurable" field. Anyway, but how can I add a field to a certain entity with all bundles, I want the admin can configure the settings, but not delete the field?
9:09 PM <bojanz> skyred: then the docs are wrong. What you want can't be done
9:09 PM <bojanz> skyred: put your settings in the widget and have them configured there