client: lib_gen: new custom plugin layout, update example plugin

- Generates new custom plugin directory layout upon `gen`
  * Allows for drop-in client-side/container-side custom plugins

- Moved container plugin example into container's plugins
  * Plugin is no longer generated upon `gen` (it's available in-repo)

- Updates plugin example
    - Provides requisite lib_finance initialization
    - Refactored, added more checks
    - Expand example case
    - Linter fixes

container/plugins/finance/example.bash

@@ -0,0 +1,77 @@
+#!/usr/bin/env bash
+
+# docker-finance | modern accounting for the power-user
+#
+# Copyright (C) 2024 Aaron Fiore (Founder, Evergreen Crypto LLC)
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+#
+# Plugins
+#
+# The plugins path (this directory) is where you can place any executable.
+# Any plugin found in this directory will be made available via the `plugins` command.
+#
+# Your plugin will have access to globals and functions provided by:
+#
+#   - finance.bash
+#   - lib_finance.bash
+#
+# The following is an example of how to create your own plugin:
+#
+
+#
+# "Libraries"
+#
+
+[ -z "$DOCKER_FINANCE_CONTAINER_REPO" ] && exit 1
+source "${DOCKER_FINANCE_CONTAINER_REPO}/src/finance/lib/lib_finance.bash"
+
+# Initialize "constructor"
+[[ -z "$global_parent_profile" || -z "$global_arg_delim_1" || -z "$global_child_profile" ]] && exit 1
+lib_finance::finance "${global_parent_profile}${global_arg_delim_1}${global_child_profile}"
+
+#
+# Implementation
+#
+
+function main()
+{
+  echo -e "
+This container's environment:
+
+$(printenv | grep ^DOCKER_FINANCE | sort)
+
+This plugin's caller profile:
+
+    ${global_parent_profile}${global_arg_delim_1}${global_child_profile}
+
+This plugin's path is:
+
+    $0
+
+This plugin's arguments:
+
+    '${*}'
+
+Showing total current BTC balance:
+"
+  echo -n "    "
+  lib_finance::ledger bal assets liabilities cur:BTC | tail -n1
+  echo
+}
+
+main "$@"
+
+# vim: sw=2 sts=2 si ai et