Installation - Support "activate first" w/setup UI

[totten]

Overview

This adds support for installing CiviCRM-Backdrop through the Setup API. Most notable changes:

• Better layout and more useful options on the installation screen
• Extensible installation logic - under the hood, this installer can initialize settings, toggle extensions, etc.
• Reusable installation logic - can run the same installation code for CLI and web UI
• No need to bypass regular module activation or bypass router (no need for install/index.php entry-point)

Before

The sysadmin downloads the CiviCRM module - but they must not install it. Instead, navigate to this path:

http://example.org/modules/civicrm/install/index.php?civicrm_install_type=backdrop

This is a special, standalone entry-point.

After

After downloading the CiviCRM module, you simply enable it like any module. Then use any link to open a CiviCRM page (e.g. there are links in the post-install status-message and in the main menu). The page will display the setup screen.

Slightly better demo: http://think.hm/tmp/Backdrop-Civicrm-Setup.mp4

Technical Details

1. The old install screen is still available as a fallback (in case there's some edge-case that got missed).
2. The basic gist of this change is:
   • Ensure that all CiviCRM-Backdrop hooks fail gracefully (in the absence of civicrm.settings.php). Most already do - there were just a couple oddballs.
   • Update the handling of civicrm/* URLs. If CiviCRM cannot initialize, then show the civicrm-setup web installer.
3. This is the same API used in the newer Civi-WP installer. (Note: For historical reasons, the Civi-WP has a few extra contingencies that aren't needed here.)
4. When testing/r-running, here are some of things that I tried:
   • Enable the module and try to view it as regular/non-admin user. Regular users cannot perform installation.
   • Install via web UI
   • Install via CLI (cv core:install -vv --cms-base-url=http://bcmaster.bknix:8001), with the civicrm.module enabled or disabled
   • Install in US English or French.
5. During development, my workflow went a bit like this:
   1. Create Backdrop site with CiviCRM codebase -- but without installing. (I specifically used a modified civibuild with the backdrop-clean type - ie hack app/config/backdrop-clean/install.sh to skip the scripted civicrm_install, etal. Then run civibuild create bcmaster or civibuild reinstall bcmaster)
   2. Login.
   3. Make a new DB snapshot (eg civibuild snapshot bcmaster). (This way my login-session is part of the snapshot.)
   4. Repeatedly do the following:
      • Edit code
      • Use the installer - and see how it goes.
      • Cleanup: ./bin/cv.phar core:uninstall -f ; civibuild restore bcmaster ; rm -rf ~/bknix/build/bcmaster/web/files/civicrm/
6. This depends on another PR for civicrm-core: Support for installing CiviCRM-Backdrop via "setup" UI civicrm-core#17749

[civibot]

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[herbdool]

I tested and left feedback here civicrm/civicrm-core#17749 (comment)