deployment: optional support for sqlite

adds optional dockerfile and docker-compose with sqlite
support/config. adds make target for alternate build.

addresses sourcegraph#140

sqlite3.Dockerfile

@@ -5,10 +5,15 @@ WORKDIR /app
 RUN apt-get install make && make build-sqlite3
 
 #---------------------------- 
-FROM golang:1.15-buster
+FROM debian:buster
 
 # install sqlite 
-RUN apt-get update && apt-get install sqlite3 && rm -rf /var/lib/apt/lists/*
+RUN apt-get update && \
+    apt-get install -y --no-install-recommends \
+    sqlite3 ca-certificates && \
+    apt-get autoremove && \
+    apt-get purge && \    
+    rm -rf /var/lib/apt/lists/*
 
 WORKDIR /app