Migrate Boost

# About

This is built on the work in the sandbox: https://www.drupal.org/sandbox/onkeltem/2828817
and
https://github.com/thinktandem/migrate_booster

On Drupal 7 we could disable hooks while running migrations:

https://www.drupal.org/node/2136601

This module adds a similar feature. You can disable hooks
in settings.php or by editing configuratoin object `migrate_boost.settings`.

There are two ways to disable hooks:

1) Disable specific hooks and modules:

```
$config['migrate_boost.settings']['hooks'] = [
# Entity insert
'entity_insert' => [
'workbench_moderation',
'pathauto',
'xmlsitemap',
],
# Entity presave
'entity_presave' => [
'xmlsitemap',
],
# Entity predelete
'entity_predelete' => [
'flag',
],
];
```

2) Disable all hooks of specific modules:

```
$config['migrate_boost.settings']['modules'] = [
'workbench_moderation',
'pathauto',
'xmlsitemap',
];
```