apk: add package

The Alpine Package Keeper is the default package manager for Alpine
Linux. They manage their own repositoriy with thousends of packages and
as musl is used for compilation, their binaries can directly run on
OpenWrt.

Signed-off-by: Paul Spooren <mail@aparcar.org>

utils/apk/patches/0001-remove-doc-generation.patch

@@ -0,0 +1,26 @@
+From b05a93c48fdbb50f0c464310dc2ce45777d32ea2 Mon Sep 17 00:00:00 2001
+From: Paul Spooren <mail@aparcar.org>
+Date: Fri, 2 Oct 2020 14:08:52 -1000
+Subject: [PATCH] remove doc generation
+
+Signed-off-by: Paul Spooren <mail@aparcar.org>
+---
+ Makefile | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/Makefile b/Makefile
+index a182269..6448917 100644
+--- a/Makefile
++++ b/Makefile
+@@ -25,7 +25,7 @@ export DESTDIR SBINDIR LIBDIR CONFDIR MANDIR DOCDIR INCLUDEDIR PKGCONFIGDIR
+ ##
+ # Top-level subdirs
+ 
+-subdirs		:= libfetch/ src/ doc/
++subdirs		:= libfetch/ src/
+ 
+ ##
+ # Include all rules and stuff
+-- 
+2.25.1
+