[WHO] Implement Rassilon, the War President

[im-inuenc]

Implement [[Rassilon, the War President]]. JUnit tests seemed fine. Abilites were tested in-game.

I used code from [[Valakut Exploration]], [[Extraordinary Journey]] (exile zone UUID/name) and [[Party Thrasher]].

To show which cards were exiled by Rassilon and who can play them, I think it might be nice to have it appear like this in-game (see screenshot below), instead of showing up in the default exile zone.
I got the idea from Extraordinary Journey. They both share UUID so if you exile a card from Rassilon and then a card from Extraordinary Journey, they show up in the same playable from exile zone now.

Just an idea - maybe it would be nice for readability of boardstate if every similar ability uses this exile zone (when the cards are not tied to any particular ability or restriction and are just castable forever).

[im-inuenc]

[[Rassilon, the War President]], [[Valakut Exploration]], [[Extraordinary Journey]], [[Party Thrasher]].

[github-actions]

Rassilon, the War President - (Gatherer) (Scryfall) (EDHREC)

{3}{U}{B}
Legendary Creature — Time Lord Noble
3/4
At the beginning of your upkeep, you lose 2 life and exile the top card of your library. You may play that card for as long as it remains exiled.
Each noncreature spell you cast from exile has conspire. (As you cast that spell, you may tap two untapped creatures you control that share a color with it. When you do, copy it and you may choose new targets for the copy.)

Valakut Exploration - (Gatherer) (Scryfall) (EDHREC)

{2}{R}
Enchantment
Landfall — Whenever a land you control enters, exile the top card of your library. You may play that card for as long as it remains exiled.
At the beginning of your end step, if there are cards exiled with this enchantment, put them into their owner's graveyard, then this enchantment deals that much damage to each opponent.

Extraordinary Journey - (Gatherer) (Scryfall) (EDHREC)

{X}{X}{U}{U}
Enchantment
When this enchantment enters, exile up to X target creatures. For each of those cards, its owner may play it for as long as it remains exiled.
Whenever one or more nontoken creatures enter, if one or more of them entered from exile or was cast from exile, you draw a card. This ability triggers only once each turn.

Unable to retrieve information for "Party Trasher"

[im-inuenc]

[[Party Thrasher]]

[github-actions]

Party Thrasher - (Gatherer) (Scryfall) (EDHREC)

{1}{R}
Creature — Lizard Wizard
1/4
Noncreature spells you cast from exile have convoke. (Each creature you tap while casting a noncreature spell from exile pays for {1} or one mana of that creature's color.)
At the beginning of your first main phase, you may discard a card. If you do, exile the top two cards of your library, then choose one of them. You may play that card this turn.