Sqlmath

- add functions dbGetLastBlob, dbTableInsertAsync
- merge file sqlmath_napi.c into sqlmath.c
- merge file test.js into sqlmath.mjs
- migrate repo to https://github.com/sqlmath/sqlmath
- migrate to esm and rename sqlmath.js to sqlmath.mjs

- merge files sqlmath.h and sqlmath_napi.c into sqlmath.c
- add async functions dbOpen, dbExec, dbClose
- inline function sqlite3_extension_functions_init without auto_extension
- disable warnings for all targets except sqlmath.c and sqlmath_napi.c
- fix build for darwin and win32.

- add addon functions dbOpen(), dbClose(), dbExec(). but ci works only in linux.

- add extension-function b64decode()
- add c-function sqlite3_exec_get_tables().
- add target_cli.
- binaries - upload darwin/linux/win32 binaries to gh-pages.
- begin compiling sqlmath.c.
- jslint file sqlmath.js.
- merge file test-old-prepare.db into test-old.js.

- add coverage testing.
- add extension-function support.
- fork repo as sqlmath.

- build: rebuild binaries before publishing [1426](https://github.com/mapbox/node-sqlite3/pull/1426)