Improve Currency submodule's Warbank functionality

[Toxicom]

Description

Recently the WunderBar's Currency submodule saw two new features added:

• Ability to summon the Warbank https://github.com/Toxicom/toxiui/commit/1391f3892752b1f1ded0402d92ad8ec8ae0ebe69
• Display Warbank CD in the tooltip https://github.com/Toxicom/toxiui/commit/cafe597bb46c24da945d289c43f26b6c62690f6e

Both of these features work fine but can be improved.

Info text cooldown

We could add the info text cooldown for the warbank summon thingy, similar to the hearthstone submodule

Tooltip update

Currently the tooltip does not update when you're hovering it -- the cooldown text for warbank updates only on hover, so you have to keep re-hovering to accurately track the cooldown

Notes

This is only for retail, errors should not leak to vanilla or cataclysm

Acceptance criteria

• Currency submodule tooltip updates dynamically to accurately display the Warbank CD
• Currency submodule has an info text displaying the correct cooldown of Warbank
• Vanilla & Cataclysm are unaffected