[Feature] Shared Deck Support

[hawkerm]

Was wanting to try playing Dandan with a friend, but apparently the OCTGN shared deck support needs support from the game extension to function. (Had originally filed there: octgn/OCTGN#2233)

Deck List:

<?xml version="1.0" encoding="utf-8" standalone="yes"?>
<deck game="a6c8d2e8-7cd8-11dd-8f94-e62b56d89593">
  <section name="Main" shared="True">
    <card qty="10" id="414d3cae-b8cf-4d53-bd6b-1aa83a828ba9">Dandân</card>
    <card qty="2" id="8d42d7aa-7f53-4cfc-842a-086aab2448d1">Brainstorm</card>
    <card qty="2" id="0aa81390-4e0b-484b-a5be-a9449cd41860">Magical Hack</card>
    <card qty="8" id="63453ed9-5cf1-4cad-b173-a067f22a4405">Memory Lapse</card>
    <card qty="2" id="a0f0c20c-184e-4d27-ae8b-933abb6fee0c">Metamorphose</card>
    <card qty="2" id="952eb6ae-a530-4f4f-92f0-a6602beaa7b2">Mind Bend</card>
    <card qty="2" id="63754036-d51e-47bb-925b-564d9dc922ff">Narset's Reversal</card>
    <card qty="2" id="04dc842c-3250-44ed-906c-38f14bf1f0e2">Predict</card>
    <card qty="2" id="9a04e9be-48be-440e-9825-cfffd4c2b1a4">Repulse</card>
    <card qty="2" id="3df927c0-9aa9-450b-ab2a-ae12c5489d57">Supplant Form</card>
    <card qty="2" id="ba5dac3d-4b49-44c4-a7b2-0a99485252c9">Unsubstantiate</card>
    <card qty="2" id="98291778-2ec2-47e2-ac99-5f8cfbb3cf24">Chart a Course</card>
    <card qty="2" id="a375ec24-4841-4792-ad58-f29cdf0d1bbb">Diminishing Returns</card>
    <card qty="2" id="e88ae6bf-9c58-4543-ba66-19ea41d01e9b">Gone Missing</card>
    <card qty="2" id="281a685a-bd02-43bf-8700-2207c65bbbb1">Mystic Retrieval</card>
    <card qty="4" id="a3584150-4f09-4c15-b13e-707bd91b3004">Take Inventory</card>
    <card qty="2" id="7b7610f3-f182-404e-80b9-ccd94e174db0">Flood Plain</card>
    <card qty="2" id="c5651e5e-2314-4e3d-a2c8-2579239314e1">Halimar Depths</card>
    <card qty="18" id="0c4eaecf-dd4c-45ab-9b50-2abe987d35d4">Island</card>
    <card qty="2" id="666f455e-3a3d-475d-b67a-a1fdd74820eb">Izzet Boilerworks</card>
    <card qty="2" id="d8ddab06-aff7-4c40-bcaa-10cbfe899dd9">Lonely Sandbar</card>
    <card qty="2" id="170e792c-80d5-4775-ad95-37614574ab84">Mystic Sanctuary</card>
    <card qty="2" id="e48d55ff-10d0-4d9b-9202-02ebb2137953">Remote Isle</card>
    <card qty="2" id="00f8ec3c-d2cb-477c-a7e8-ff497df646d6">Temple of Epiphany</card>
  </section>
  <section name="Sideboard" shared="False" />
  <section name="Command Zone" shared="False" />
  <section name="Planes/Schemes" shared="False" />
  <notes><![CDATA[]]></notes>
</deck>