Faster initial database creation (#12297)

* Faster initial database creation
Add db dumps to improve initial db migration
On my test system 13s -> 7s, a 46% reduction.
Should help out a lot on systems like RPi

* lnms schema:dump command

--snapshots saves db snapshots, otherwise it saves the yaml

* fix style

* fix timezones...

* not working with in-memory db yet
remove build.sql

scripts/build-schema.php

@@ -1,14 +0,0 @@
-#!/usr/bin/env php
-<?php
-
-$install_dir = realpath(__DIR__ . '/..');
-
-// update.php will call init.php
-require $install_dir . '/includes/sql-schema/update.php';
-
-$file = $install_dir . '/misc/db_schema.yaml';
-$yaml = Symfony\Component\Yaml\Yaml::dump(dump_db_schema(), 3, 2);
-
-if (file_put_contents($file, $yaml)) {
-    echo "Updated!\n";
-}