fix: update to modern defaults for Debian family

Don't add key_url as it is deprecated and not needed when
pkgrepo_keyring is set. This has been supported since stretch so make it
the default. Also use py3 repo by default for Debian family as it is now
the only option.

Additionally, Raspbian has been updated to use signed-by by default.

pillar.example

   master_remove_config: true
 
   # Set this to 'py3' to install the Python 3 packages.
-  # If this is not set, the Python 2 packages will be installed by default.
+  # The default varies between OS versions.
   py_ver: 'py3'
 
   # Set this to false to not have the formula install packages (in the case you

salt/osfamilymap.yaml

 
 
 Debian:
-  pkgrepo: 'deb [signed-by=/usr/share/keyrings/salt-archive-keyring.gpg arch=amd64] {{ salt_repo }}/{{ py_ver_repr or 'apt' }}/{{ osfamily_lower }}/{{ osmajorrelease }}/amd64/{{ salt_release }} {{ oscodename }} main'
-  key_url: '{{ salt_repo }}/{{ py_ver_repr or 'apt' }}/{{ osfamily_lower }}/{{ osmajorrelease }}/amd64/{{ salt_release }}/SALTSTACK-GPG-KEY.pub'
-  pkgrepo_keyring: '{{ salt_repo }}/{{ py_ver_repr or 'apt' }}/{{ osfamily_lower }}/{{ osmajorrelease }}/amd64/{{ salt_release }}/salt-archive-keyring.gpg'
+  pkgrepo: 'deb [signed-by=/usr/share/keyrings/salt-archive-keyring.gpg arch=amd64] {{ salt_repo }}/{{ py_ver_repr or 'py3' }}/{{ osfamily_lower }}/{{ osmajorrelease }}/amd64/{{ salt_release }} {{ oscodename }} main'
+  pkgrepo_keyring: '{{ salt_repo }}/{{ py_ver_repr or 'py3' }}/{{ osfamily_lower }}/{{ osmajorrelease }}/amd64/{{ salt_release }}/salt-archive-keyring.gpg'
   pkgrepo_keyring_hash: sha256=ea38e0cdbd8dc53e1af154a8d711a2a321a69f81188062dc5cde9d54df2b8c47
   libgit2: libgit2-22
   pyinotify: python-pyinotify

salt/osmap.yaml

         install_from_package: Null
 
 Raspbian:
-  pkgrepo: 'deb {{ salt_repo }}/{{ py_ver_repr or 'apt' }}/{{ os_family_lower }}/{{ osmajorrelease }}/armhf/{{ salt_release }} {{ oscodename }} main'
-  key_url: '{{ salt_repo }}/{{ py_ver_repr or 'apt' }}/{{ os_family_lower }}/{{ osmajorrelease }}/armhf/{{ salt_release }}/SALTSTACK-GPG-KEY.pub'
+  pkgrepo: 'deb [signed-by=/usr/share/keyrings/salt-archive-keyring.gpg arch=armhf] {{ salt_repo }}/{{ py_ver_repr or 'py3' }}/{{ os_family_lower }}/{{ osmajorrelease }}/armhf/{{ salt_release }} {{ oscodename }} main'
+  pkgrepo_keyring: '{{ salt_repo }}/{{ py_ver_repr or 'py3' }}/{{ os_family_lower }}/{{ osmajorrelease }}/armhf/{{ salt_release }}/salt-archive-keyring.gpg'
 
 SmartOS:
   salt_master: salt

test/integration/v3001-py3/files/_mapdata/debian-10.yaml

           version: 0.23.0
         version: 0.22.1
     install_packages: true
-    key_url: https://repo.saltproject.io/py3/debian/10/amd64/3001/SALTSTACK-GPG-KEY.pub
     libgit2: libgit2-22
     master:
       ext_pillar:

test/integration/v3001-py3/files/_mapdata/debian-9.yaml

           version: 0.23.0
         version: 0.22.1
     install_packages: true
-    key_url: https://repo.saltproject.io/py3/debian/9/amd64/3001/SALTSTACK-GPG-KEY.pub
     libgit2: libgit2-22
     master:
       ext_pillar:

test/integration/v3002-py3/files/_mapdata/debian-10.yaml

           version: 0.23.0
         version: 0.22.1
     install_packages: true
-    key_url: https://repo.saltproject.io/py3/debian/10/amd64/3002/SALTSTACK-GPG-KEY.pub
     libgit2: libgit2-22
     master:
       ext_pillar:

test/integration/v3002-py3/files/_mapdata/debian-9.yaml

           version: 0.23.0
         version: 0.22.1
     install_packages: true
-    key_url: https://repo.saltproject.io/py3/debian/9/amd64/3002/SALTSTACK-GPG-KEY.pub
     libgit2: libgit2-22
     master:
       ext_pillar: