Moving admin index route to bottom of routes file to allow it to be overridden without breaking pagination on the orders page

Fixes #5461
Update jquery-ui-rails

Fixes #5462
Remove 'disabled' from inputs in payments

With the Aug 27 commit, a601035bd199a49f7f74ccf04ed0d889ca895f3e, the inputs under `.payment-method` are being disabled on line 15 but never correctly undisabled. This fixes that issue. Looks like it is affecting most branches.
fixes #5467
fix handling of credit cards expiring in current month
fixes #5468
Ignore guides.
Use Rails environments instead of DB configurations

In the admin forms for Spree::PaymentMethod and Spree::Tracker the collection used for the environment field is the database configuration keys. This is wrong and it becomes quite apparent in the case of applications that connect to more than one database. This commit replaces said collection with a collection of the available environment configurations in '/config/environments/'.

Closes #5170
Add issuestats badges.
Make best-promotion query more deterministic

Mostly for the benefit of the specs under MySQL.

This query was generating some sporadic spec failures for me when using MySQL as the database. This is because MySQL does not store fractional seconds so the "created_at" was sometimes the same value for two adjustments when running specs. And when created_at is identical the query below would actually pick the earlier adjustment instead of the more recent one.  Adding "id" as a fallback ordering fixes this problem and makes the behavior more deterministic.

The issue is reproduceable in postgres as well by using Timecop.

Fixes #4943