Implement D8 initialization for civicrm-setup

[monishdeb]

https://github.com/civicrm/civicrm-setup/issues/10

[monishdeb]

This is how I tested from php

try {
  \Civi\Cv\CmsBootstrap::singleton()->bootCms()->bootCivi();
}
catch (Exception $e) {
}

  \Civi\Setup::assertProtocolCompatibility(1.0);
  \Civi\Setup::init([
    "srcPath"=> "/Users/monish/src/civicrm",
    "setupPath"=> "/Users/monish/src/civicrm-setup",
    "cms"=> "Drupal8",
    "cmsBaseUrl"=> "http://localhost:8888/test-drupal8/",
    "db"=> [
      "server"=> "127.0.0.1:8889",
      "username"=> "root",
      "password"=> "root",
      "database"=> "test_drupal8"
  ]]);
  $setup = Civi\Setup::instance();
  if (!$setup->checkAuthorized()->isAuthorized()) {
    exit("Sorry, you are not authorized to perform installation.");
  }
  $setup->installFiles();
  $setup->installDatabase();

[totten]

I haven't tested on D8, but I'm inclined to merge anyway. Some considerations:

• Tested on D7 and WP, with en_US and fr_FR -- and they still installed fine. Also, I ran cv's installation test-suite, and that still passes.
• The patch generally reads OK.
• The overall D8/composer effort requires multiple patches, and it's easier to test/reproduce if we don't have to manually apply all of them.
• Changes in this repo won't go public until we tag a new release and update composer.{json,lock} for civicrm-core.

Thank you, @monishdeb!

[monishdeb]

Thanks you @totten for merging this PR :)