added event hooks

[therealkevinard]

This PR causes the plugin to dispatch events through the October framework before and after saving a record, in order for others to extend the action with custom handlers.

This is to better support issues along the lines of:

• Make different table for each form #5
• Asking the Basic #46

A snippet implementation from my use-case:

• from https://github.com/therealkevinard/oc-plugin-rwm-mfcontactsview

<?php namespace Rwm\MfContactsView;

use Illuminate\Support\Facades\Event;
use System\Classes\PluginBase;

class Plugin extends PluginBase
{
    // ... other plugin setup ... 
    
    public function boot()
    {
        /**
         * In my particular use-case, I've used this event hook in a custom plugin to render the form data in a tailored way. A lightweight backend plugin in my namespace
         *  listend for the MF beforeSaveRecord, and performs custom mutation\persistence with the raw form data passed along with the event.
         *
         *  Magic Forms still manages all front-end display, and manages datastore for all forms - but client pushed for this specific form to have a certain view.
         */
        Event::listen('martin.forms.beforeSaveRecord', function ($formdata) {
            $contact = json_decode($formdata);
            xdebug_break();
            //-- Now do something with $formdata (which contains the complete json_encode of the original form data.)
        });

        Event::listen('martin.forms.afterSaveRecord', function ($formdata) {
            $contact = json_decode($formdata);
            xdebug_break();
        });
    }

    // ... other plugin setup ... 

}

[skydiver]

Hello @therealkevinard, excellent addition to the plugin.

I will be merging right now, thanks a lot!