init.lua: rewrite nvim entrypoint to use psoxizsh.entrypoint

Plus, add a detailed description of the new location(s) for configuration, and
a brief overview of how plugins work

init.lua

@@ -1,3 +1,94 @@
+--[[
+  This is entrypoint Psoxizsh uses to start Neovim.
+
+  The majority of configuration can be done via the following files:
+
+    ~/.config/nvim
+    ├── lua
+    │   ├── config
+    │   │   ├── autocmds.lua      | Any additional autocmds (late loaded)
+    │   │   ├── keymaps.lua       | Any additional key binds (late loaded)
+    │   │   ├── lazy.lua          |
+    │   │   └── options.lua       | Any vim.opt or vim.g configuration (early loaded)
+    │   └── plugins               | Any additional plugins, changes to existing
+    │       ├── spec1.lua         | plugins, plugin specific key binds, etc.
+    │       └── specN.lua         |
+    └── init.lua                  | <--- You are here
+
+
+  autocmds.lua:
+    Any custom autocommands to create.
+
+    You can use `psoxizsh.autocmd` as a helper for creating these.
+
+    Example:
+      local au = psoxizsh.autocmd
+
+      au.MyCustomGroup {
+        { 'VimEnter', 'yaml', ':silent echo opened a YAML file!' }
+      }
+
+  keymaps.lua:
+    Any additional key binds to create.
+
+    You can use the builtin `vim.keymap.set` to create these. See :h vim.keymap
+    for more details.
+
+    Example:
+      local map = vim.keymap.set
+
+      map('n', '<leader>:', function() print('using a lua function') end)
+      map({ 'i', 'v' }, '<leader>:', '<cmd>silent echo using a vim cmdstring<CR>')
+
+  options.lua:
+    Any extra options you wish to set.
+
+    Unlike other files, options.lua is loaded *EARLY*, before most initialization
+    happens, letting you set things like mapleader, background color, etc before
+    other things that use this information are loaded.
+
+    However, this also means that (excluding parts of psoxizsh itself) you cannot
+    access any plugin related configuration.
+
+    Example:
+      local opt, g = vim.opt, vim.g
+
+      g.mapleader = ','
+
+  plugins/*.lua
+    Any direct submodules in the plugin/ directory will have their plugin specs
+    merged and loaded during initialization.
+
+    A full description of a plugin is beyond the purview of this document, but
+    briefly, each spec object describes where to source it, how to configure it,
+    when to load it, and any additional plugins it depends on.
+
+    These specs are then merged according to the following rules:
+      - cmd         : the list of commands will be extended with your custom commands
+      - event       : the list of events will be extended with your custom events
+      - ft          : the list of filetypes will be extended with your custom filetypes
+      - keys        : the list of keymaps will be extended with your custom keymaps
+      - opts        : your custom opts will be merged with the default opts
+      - dependencies: the list of dependencies will be extended with your custom dependencies
+      - any other property will override the defaults
+
+    See https://lazy.folke.io/spec for the full spec description, or look at
+    some of the examples in $PSOXIZSH/nvim/lua/psoxizsh/plugins for more.
+
+  ---
+
+  Unless you wish to change the options passed directly to our package manager,
+  you do not need to change this file. If you do, copy this file to your local
+  ~/.config/nvim/init.lua and make the modifications needed:
+
+    cp -v $PSOXIZSH/init.lua ~/.config/nvim/init.lua
+
+  Next, add the following line (replacing 'overrides' with your config overrides)
+  just above the call to .start():
+
+    require('psoxizsh.entrypoint.config').with(overrides)
+--]]
+
 vim.opt.rtp:append( os.getenv('PSOXIZSH') .. '/nvim' )
 
-require 'psoxizsh'
+require('psoxizsh.entrypoint').start()