docker: luarocks, luaflock, lua-sql-sqlite3

Some useful packages that a user might want available to their
Lua scripts:

- `luaflock`: BSD-style flock
- `lua-sql-sqlite3`: SQLite bindings for Lua

Also print the lua error code and error message string in the error
handler. It seems like not all Lua errors have stack traces/tracebacks,
e.g. requiring a non-existent module:

before:

```
lua runtime error:
terminate called after throwing an instance of 'OsmLuaProcessing::luaProcessingException'
  what():  std::exception
```

after:

```
lua runtime error 2:
./file_append.lua:7: module 'flock' not found:
	no field package.preload['flock']
	no file './flock.lua'
	no file '/usr/local/share/lua/5.1/flock.lua'
	no file '/usr/local/share/lua/5.1/flock/init.lua'
	no file '/usr/local/lib/lua/5.1/flock.lua'
	no file '/usr/local/lib/lua/5.1/flock/init.lua'
	no file '/usr/share/lua/5.1/flock.lua'
	no file '/usr/share/lua/5.1/flock/init.lua'
	no file './flock.so'
	no file '/usr/local/lib/lua/5.1/flock.so'
	no file '/usr/lib/x86_64-linux-gnu/lua/5.1/flock.so'
	no file '/usr/lib/lua/5.1/flock.so'
	no file '/usr/local/lib/lua/5.1/loadall.so'
terminate called after throwing an instance of 'OsmLuaProcessing::luaProcessingException'
  what():  std::exception
```

Dockerfile

@@ -9,9 +9,11 @@ RUN apt-get update && DEBIAN_FRONTEND=noninteractive apt-get install -y --no-ins
     libboost-program-options-dev \
     libboost-filesystem-dev \
     libboost-system-dev \
+    luarocks \
     rapidjson-dev \
     cmake && \
-    rm -rf /var/lib/apt/lists/*
+    rm -rf /var/lib/apt/lists/* && \
+    luarocks install luaflock
 
 WORKDIR /usr/src/app
 
@@ -35,13 +37,15 @@ RUN apt-get update && DEBIAN_FRONTEND=noninteractive apt-get install -y --no-ins
     liblua5.1-0 \
     shapelib \
     libsqlite3-0 \
+    lua-sql-sqlite3 \
     libboost-filesystem1.74.0 \
     libboost-program-options1.74.0 && \
     rm -rf /var/lib/apt/lists/*
 
 WORKDIR /usr/src/app
 COPY --from=src /usr/src/app/build/tilemaker .
 COPY --from=src /usr/src/app/build/tilemaker-server .
+COPY --from=src /usr/local/lib/lua/5.1/flock.so /usr/local/lib/lua/5.1/flock.so
 COPY resources ./resources
 COPY process.lua ./
 COPY config.json ./

src/osm_lua_processing.cpp

@@ -199,7 +199,8 @@ bool supportsRemappingShapefiles = false;
 
 int lua_error_handler(int errCode, const char *errMessage)
 {
-	std::cerr << "lua runtime error: " << std::endl;
+	std::cerr << "lua runtime error " << std::to_string(errCode) << ":" << std::endl;
+	std::cerr << errMessage << std::endl;
 	kaguya::util::traceBack(g_luaState->state(), errMessage); // full traceback on 5.2+
 	kaguya::util::stackDump(g_luaState->state());
 	throw OsmLuaProcessing::luaProcessingException();