[MKM] Implement Cryptic Coat

[Susucre]

Implement Cryptic Coat (and it's cloak effect) adding a boolean to ManifestEffect/doManifestCards.

It is functional and works in my alpha server.
It does share the current bugs for Manifest and more generally Face Down, and does not show the Ward {2} properly like Disguise. Other than that it works fine enough.

In my opinion it could be merged like this in the beta. I don't really care if not, just wanted to share the work done as a courtesy. I don't plan to add/tweak it, so feel free to do it.

Note: maintainers edits are voluntarily disabled, since I'm using the branch on my repo for the alpha build. Cherry-pick the commit in your own branch/PR if you desire to use and tweak.

[github-actions]

Cryptic Coat - (Gatherer) (Scryfall) (EDHREC)

{2}{U}
Artifact — Equipment
When Cryptic Coat enters the battlefield, cloak the top card of your library, then attach Cryptic Coat to it. (To cloak a card, put it onto the battlefield face down as a 2/2 creature with ward {2}. Turn it face up any time for its mana cost if it's a creature card.)
Equipped creature gets +1/+0 and can't be blocked.
{1}{U}: Return Cryptic Coat to its owner's hand.

[Susucre]

Turning the right one face up: