Feature Request: Search pods items in single item shortcode / widget

[justaguy84]

Issue Overview

When using single item widget, we need to enter the ID or slug of the item we want.
Search option (like the list on a custom field) will help find the correct item without knowing the ID.

Expected Behavior

Same UI/UX as in list options for custom fields in pods to allow a search for items for the pods selected.

Current Behavior

We need to know the ID or slug and input it manually.

WordPress Environment

``` WordPress Version: 4.9.8

PHP Version: 7.2.12-1+ubuntu16.04.1+deb.sury.org+1

MySQL Version: 5.5.5

Server Software: nginx/1.15.6

Your User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/70.0.3538.77 Safari/537.36

Session Save Path: /var/lib/php/sessions

Session Save Path Exists: No

Session Save Path Writeable: No

Session Max Lifetime: 1440

Opcode Cache:

Apc: No
Memcached: No
OPcache: Yes
Redis: No
Object Cache:

APC: No
APCu: Yes
Memcache: No
Memcached: Yes
Redis: Yes
WPDB Prefix: wp_

WP Multisite Mode: No

WP Memory Limit: 40M

Pods Network-Wide Activated: No

Pods Install Location: /www/topaustraliancasinos_596/public/wp-content/plugins/pods/

Pods Tableless Mode Activated: No

Pods Light Mode Activated: No

Currently Active Theme: Rehub child theme

Currently Active Plugins:

Coming Soon Page & Maintenance Mode by SeedProd: 5.0.23
Enable Media Replace: 3.2.7
Envato Market: 2.0.1
Pods - Custom Content Types and Fields: 2.7.9
RH WooCommerce Tools: 1.1.0
ThirstyAffiliates: 3.4.0
WooCommerce: 3.5.1
WPBakery Page Builder: 5.5.5
Yoast SEO: 9.1

</details>