build core, basic and go variants and add template

template/Containerfile

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+FROM code-basic
+USER root
+ENV HOME=/root
+
+# Install alpine packages
+### 
+### Replace ...  with the alpine packaes you'd like to install.
+### You can browser them on https://pkgs.alpinelinux.org/packages.
+###
+RUN apk add --no-cache ...
+
+# Install neovim plugins
+### 
+### Replace the first ...  with <user>/<repo> strings for every neovim plugin
+### you'd like to install from GitHub. Replace the second ... with a comma
+### separated list of the <repo>s, that contain a doc directory.
+###
+WORKDIR /usr/local/share/nvim/site/pack/plugins/opt
+RUN printf '%s\n' \
+  ... \
+  | xargs -n1 -P0 -I'{}' git clone --depth 1 'https://github.com/{}'
+RUN printf 'helptags %s\n' {...}/doc | nvim --noplugin -es
+
+# Add neovim config
+COPY nvim /etc/xdg/nvim
+
+###
+### Execute further instructions and copy furhter configurations here.
+###
+
+# Configure environment
+USER 1000:1000
+ENV HOME=/tmp

template/nvim/init/template.lua

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+local pack = require 'pack'
+
+---
+--- Add your custom neovim configuration here. This file should be named after
+--- your editor variant. You can use `pack '<user>/<repo>'` to load a plugin
+--- and source it's configuration file. For a plugin
+--- 'my-user/nvim-my-repo.nvim', the configuration file plugconf/my-repo.lua
+--- would be source, if it exists ("nvim-" and "vim-" prefixes and everyting
+--- after the first "." get removed from <repo>).
+---
+
+pack 'my-user/nvim-my-repo.nvim'

template/nvim/luasnippets/all.lua

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+---
+--- Add your lua snippets here. Rename this file to match the file type your
+--- snippets are supposed to be availlable for instead of 'all'.
+---
+
+return {
+  parse(
+    { trig = 'my-snippet', name = 'My Snippet' },
+    'The quick brown ${1:fox} jumps over the lazy ${2:dog,cat,elephant}'
+  ),
+}

template/plugconf/my-repo.lua

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+---
+--- You can import your plugin and set it up or set vim options to configure it
+--- here. If any of your plugins don't require configuration, you can simply
+--- omit creating a plugconf/*.lua file for it.
+---

template/podman.args

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+###
+### Add variant specific podman arguments here, one per line, or remove the
+### file entirely. You can use {DIR} as placeholder for the directory of this
+### repository, {NAME} for the name of the current working directory, that will
+### be mounted to /work/{NAME} in the container and {HOME} for the users home
+### directory on the host system. That way you can change the confinement or
+### network configuration, mount additional directories into the container etc.
+###