Expand more path in configuration

[baby-gnu]

Is your feature request related to a problem? Please describe.

Sharing my salt-ssh personal configuration can't be done easily since several configuration path do not support

• tilde (~) expansion
• path relative to root_dir

Another scenario is to use salt as a master-less provisionning for cloud images where I can't use salt-ssh (in a chroot for example): I would like to be able to mount a directory in my chroot and make the provisionning working with salt-call.

Describe the solution you'd like

I would like to be able to define several configuration relative to my home directory using tilde or even path relative to root_dir:

~/.salt/Saltfile

salt-ssh:
  config_dir: ~/.salt

~/.salt/master

root_dir: ~/.salt

file_roots:
   base:
     - ~/.salt/srv/salt/

pillar_roots:
  base:
    - ./srv/pillar/ # Is the same as ~/.salt/srv/pillar

ext_pillar:
  # https://docs.saltproject.io/en/latest/ref/pillar/all/salt.pillar.stack.html
  - stack:
    - ~/.salt/srv/pillar/common.cfg
    # `roles.cfg` can use data from `common.cfg` through `stack.get()`
    - ~/.salt/srv/pillar/roles.cfg

Describe alternatives you've considered

No real alternative to this, only sed the configuration files.

Additional context

This is a reopen of #14613 because it was closed for old and python2 reasons but it still apply, so reset age counter ;-)

It's still related to #51192.

Please Note
If this feature request would be considered a substantial change or addition, this should go through a SEP process here https://github.com/saltstack/salt-enhancement-proposals, instead of a feature request.

[baby-gnu]

Hello @OrangeDog, it's not restricted to salt-ssh ;-)