feat: add Dockerfile to parametrically build from alpine

Dockerfile

@@ -0,0 +1,28 @@
+ARG ALPINE_VERSION=edge
+FROM docker.io/alpine:${ALPINE_VERSION}
+
+ARG POWERDNS_VERSION=4.9.4-r0
+# Enable community repo
+RUN apk add --no-cache alpine-conf
+RUN setup-apkrepos -c
+RUN apk del alpine-conf
+RUN apk --no-cache add \
+  "pdns=${POWERDNS_VERSION}" \
+  pdns-backend-bind \
+  pdns-backend-ldap \
+  pdns-backend-lmdb \
+  pdns-backend-mariadb \
+  pdns-backend-mysql \
+  pdns-backend-pgsql \
+  pdns-backend-mariadb \
+  pdns-backend-sqlite3 \
+  pdns-backend-odbc \
+  pdns-backend-pipe \
+  pdns-backend-remote \
+  pdns-backend-lua2 \
+  libcap
+
+RUN setcap 'cap_net_bind_service=+eip' /usr/sbin/pdns_server
+SHELL ["/bin/bash", "-c"]
+
+CMD ["/usr/sbin/pdns_server"]