Configuration pipeline / processors

[tony]

This is needed for easier completion / testability and making listing of configs more accessible

1. Find configs
2. Parse configs (yaml, strictyaml, json, jsonc, toml)
3. Modify configs (e.g. expand configs/shorthand_
4. Workspace endpoints

See also the Config loaders and backends from vcs-python/vcspull#351

• Builds an immutable list of build_config_index(**options), ConfigIndex or ConfigList. Reads all configs, configurable, optionally include (filter?)

  Make into a class that can be instantiated / reused / a singleton?

  c = Configs()
c.configs
c.search() - if even?

  It needs to know about current working directory, user-space configs (e.g. XDG_DIRS), system-level configs (also XDG)

  It likely won't know about project based configs but we can add loaders to "Look up" in a current project for a project-based config e.g. ~/work/projects/tmuxp/.tmuxp.yaml, being able to see it from CWD of ~/work/projects/tmuxp/docs/configuration

• Of if staying in list form

  Return an immutable list configs search_configs()