examples: add minimal templates example

A simple project demonstrating apkg templating features.

examples/templates/README.md

+# apkg example project: templates
+
+This minimal project demonstrates apkg templating features.
+
+Looking at 'package templates' section of
+
+    apkg status
+
+as well as
+
+    ls -la distro/pkg
+
+should be self-explanatory.
+
+Custom templates are defined in distro/config/apkg.toml
+
+## tests
+
+This project is used in apkg self tests:
+
+* tests/self/test_templates.py

examples/templates/distro/config/apkg.toml

+[project]
+name = "templates"
+make_archive_script = "distro/scripts/make-archive.sh"
+
+[apkg]
+compat = 1
+
+[[distro.aliases]]
+name = "deb-old"
+distro = ["debian <= 9", "ubuntu < 20.04"]
+
+[[distro.aliases]]
+name = "el-8"
+distro = ["rocky == 8", "centos == 8", "rhel == 8"]

examples/templates/distro/pkg/deb-old

+deb
\ No newline at end of file

examples/templates/distro/pkg/deb/changelog

+apkg-example-templates ({{ version }}-{{ release }}~{{ distro.tiny }}) unstable; urgency=medium
+
+  * new upstream version {{ version }}
+  * distro: {{ distro }} / {{ distro.idver }} / {{ distro.tiny }}
+{%- if distro.match('debian >= 11', 'ubuntu > 20.04') %}
+  * new Debian-based
+{%- elif distro.match('deb-old') %}
+  * old Debian-based (distro alias)
+{%- elif distro.match('linuxmint') %}
+  * only on Linux Mint
+{%- else %}
+  * other Debian-based
+{%- endif %}
+
+ -- Jakub Ružička <jakub.ruzicka@nic.cz>  {{ now }}

examples/templates/distro/pkg/deb/compat

+9

examples/templates/distro/pkg/deb/control

+Source: apkg-example-templates
+Priority: optional
+Maintainer: Jakub Ružička <jakub.ruzicka@nic.cz>
+Homepage: https://gitlab.nic.cz/packaging/apkg
+
+Package: apkg-example-templates
+Architecture: all
+Description: minimal example of apkg templating system

examples/templates/distro/pkg/deb/copyright

+Format: https://www.debian.org/doc/packaging-manuals/copyright-format/1.0/
+Upstream-Name: apkg
+Source: https://gitlab.nic.cz/packaging/apkg
+
+Files: *
+Copyright: (c) 2020-2021, Jakub Ružička <jakub.ruzicka@nic.cz>
+License: GPL-3+
+
+License: GPL-3+
+ 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/>.
+ .
+ On Debian systems, the full text of the GNU General Public License
+ version 3 can be found in the file `/usr/share/common-licenses/GPL-3'.

examples/templates/distro/pkg/deb/rules

+#!/usr/bin/make -f
+%:
+	dh $@

examples/templates/distro/pkg/deb/source/format

+3.0 (quilt)

examples/templates/distro/pkg/debian-10

+deb
\ No newline at end of file

examples/templates/distro/pkg/el-8

+rpm
\ No newline at end of file

examples/templates/distro/pkg/rocky

+rpm
\ No newline at end of file

examples/templates/distro/pkg/rpm/apkg-example-templates.spec

+Name:             apkg-example-templates
+Version:          {{ version }}
+Release:          {{ release }}%{?dist}
+Summary:          minimal example of apkg templating system
+
+License:          GPL 3.0
+Source0:          %{name}-v%{version}.tar.gz
+
+BuildArch:        noarch
+
+%description
+This is a minimal example of apkg templating features.
+
+%prep
+%autosetup -n %{name}-v%{version} -S git
+
+%files
+%doc README.md
+
+%changelog
+* {{ now }} Jakub Ružička <jakub.ruzicka@nic.cz> - {{ version }}-{{ release }}
+- new upstream version {{ version }}
+- distro: {{ distro }} / {{ distro.idver }} / {{ distro.tiny }}
+{%- if distro.match('fedora') %}
+- Fedora-specific block
+{%- elif distro.match('centos <= 7', 'rhel <= 7') %}
+- only on EL 7 and older
+{%- elif distro.match('el-8') %}
+- only on EL 8 (distro alias)
+{%- endif %}

examples/templates/distro/pkg/ubuntu

+deb
\ No newline at end of file

examples/templates/distro/pkg/ubuntu-20.04

+deb
\ No newline at end of file

examples/templates/distro/scripts/make-archive.sh

+#!/bin/bash
+# create archive containing only README.md in a directory
+set -e
+
+VERSION=1.0
+OUTPATH=pkg/archives/dev
+NAMEVER=apkg-example-templates-v$VERSION
+TOPDIR=templates
+ARCHIVE=$NAMEVER.tar.gz
+ARPATH=$OUTPATH/$ARCHIVE
+
+mkdir -p "$OUTPATH"
+mkdir -p "$NAMEVER"
+cp README.md "$NAMEVER/"
+tar -czvf "$ARPATH" "$NAMEVER"
+rm -rf  "$NAMEVER"
+
+# apkg expects stdout to list archive files
+echo $ARPATH