Remove sqlite3 module

It's not clear that this ever worked, AFAICT nobody uses it, and it's an
old version of the sqlite3 engine at this point.  Absent a maintainer,
let's just get rid of it.

app/Makefile

@@ -25,7 +25,7 @@ endif
 ifndef PDIR # {
 GEN_IMAGES= eagle.app.v6.out
 GEN_BINS= eagle.app.v6.bin
-OPT_MKTARGETS        := coap dht http mqtt pcm sjson sqlite3 tsl2561 websocket
+OPT_MKTARGETS        := coap dht http mqtt pcm sjson tsl2561 websocket
 OPT_MKLIBTARGETS     := u8g2 ucg
 SEL_MKTARGETS        := $(shell $(CC) -E -dM include/user_modules.h | sed -n '/^\#define LUA_USE_MODULES_/{s/.\{24\}\(.*\)/\L\1/; p}')
 OPT_SEL_MKLIBTARGETS := $(foreach tgt,$(OPT_MKLIBTARGETS),$(findstring $(tgt), $(SEL_MKTARGETS)))

app/include/user_modules.h

@@ -59,7 +59,6 @@
 //#define LUA_USE_MODULES_SOFTUART
 //#define LUA_USE_MODULES_SOMFY
 #define LUA_USE_MODULES_SPI
-//#define LUA_USE_MODULES_SQLITE3
 //#define LUA_USE_MODULES_STRUCT
 //#define LUA_USE_MODULES_SWITEC
 //#define LUA_USE_MODULES_TCS34725