client: docker: complete build overhaul, optimize

This commit brings a complete overhaul of the build system:

- Creates a separation of concerns for 'local' and 'remote' building
  * 'local' is built locally via the docker-finance `build` command
  * 'remote' is built *outside* of the docker-finance `build` command
    (pushed to a remote registry and then pulled by the 'local' build)
  * Related refactoring
    - Dockerfiles
    - `lib_gen`

- Adds remote image 'hledger-suite'
  * Provides the latest versions of all `hledger` related binaries
  * No longer relies on package maintainers / out-dated packages

- Adds remote image 'docker-finance'
  * Provides base image for 'finance' and 'dev-tools' images
    - tags 'archlinux' | 'ubuntu' | 'dev-tools'

- Removes previous `hledger` related build modules
  * Removes building any `hledger` related binaries locally

- Removes 'experimental' build
  * End-user can use local custom Dockerfile and/or custom tag instead

- Updates the 'default' | 'slim' | 'tiny' | 'micro' build types
  * Refactors build type requirements into separate build modules
    - Adds 'fetch' module
    - Adds 'track' module
    - Adds 'user' module
      * creates container user *after* base and all other modules
      * allows for quick re-building across multiple local users
    - Updates 'root' module
  * `lib_docker`
    - Updates usage help
    - Adds build modules per build type

- Huge optimizations
  * Vastly improves build times
    - ~60% faster w/ a fresh build
    - ~60%-90% faster rebuild (depending on image type)
  * Vastly improves image sizes
    - e.g., 'default' Arch Linux image size is ~50% smaller

client/src/docker/lib/internal/lib_gen.bash

@@ -203,7 +203,7 @@ function lib_gen::__set_client_globals()
   lib_utils::print_debug "global_platform_image=${global_platform_image}"
 
   # Base location of Docker-related files (.in and final out files)
-  global_repo_dockerfiles="${DOCKER_FINANCE_CLIENT_REPO}/client/Dockerfiles/${global_platform_image}"
+  global_repo_dockerfiles="${DOCKER_FINANCE_CLIENT_REPO}/client/Dockerfiles/local/${global_platform_image}"
   # shellcheck disable=SC2034  # used in lib_docker
   declare -g global_repo_dockerfiles
   lib_utils::print_debug "global_repo_dockerfiles=${global_repo_dockerfiles}"