Refactor Package structure

This commit cleans up the package structure, to make two new top-level
packages `internal` (for internal-use packages) and `pkg` (for general
shared utility code).

internal/component/triplestore/stack/docker-compose.yml

@@ -0,0 +1,22 @@
+version: "3.7"
+
+services:
+    triplestore:
+        build: .
+        ports:
+            - "127.0.0.1:7200:7200"
+        volumes:
+            - './data/data:/opt/graphdb/data'
+            - './data/work:/opt/graphdb/work'
+            - './data/logs:/opt/graphdb/logs'
+        command: "\"-Dgraphdb.home=/opt/graphdb -Ddefault.min.distinct.threshold=2G\""
+        # Use 1GB of heap space
+        environment:
+            GDB_HEAP_SIZE: 16G
+
+        restart: always
+
+networks:
+    default:
+        name: distillery
+        external: true