Update root-level README and reorganize sources

In an effort to mitigate questions from new, inexperienced users on how
to import data into Fight Club 5e, I rewrote and reorganized the
root-level README file to include detailed instructions on how to
compile their own compendiums using the sources found within this
repository. Some existing data, such as how to create your own
collection file, was moved into other READMEs under the Collections and
Sources directories.

I also took some liberty in reorganizing the directory structure of this
repository and renamed some of the top-level directories. In my view,
having sources under the "FightClub5eXML" folder didn't make a lot of
sense, so I moved those sources into the top-level "Sources" folder. I
made sure to update all of the collection files, along with the
"travis.yml" config file, to properly point to the correct folders.

Finally, while updating the "travis.yml" config file, I changed the
output folder of those build compendiums to be under a top-level
"Compendiums" folder. This folder is ignored by git.

Sources/UnearthedArcana/bestiary-ua-20s2.xml

@@ -0,0 +1,47 @@
+<?xml version='1.0' encoding='utf-8'?>
+<compendium version="5" auto_indent="NO">
+    <monster>
+      <name>Dancing Item (UA)</name>
+    <size>L</size>
+    <type>construct</type>
+    <alignment>Neutral</alignment>
+    <ac>16 (natural armor)</ac>
+    <hp>3</hp>
+    <speed>walk 40 ft.</speed>
+    <str>18</str>
+    <dex>14</dex>
+    <con>16</con>
+    <int>4</int>
+    <wis>10</wis>
+    <cha>6</cha>
+    <save></save>
+    <skill></skill>
+    <passive>10</passive>
+    <languages>understands the languages you speak</languages>
+    <cr></cr>
+    <resist></resist>
+    <immune>poison</immune>
+    <vulnerable></vulnerable>
+    <conditionImmune>charmed, exhaustion, poisoned, frightened</conditionImmune>
+    <senses>darkvision 60 ft.</senses>
+    <trait>
+        <name>Hit Points</name>
+      <text>equal the Dancing Item (UA)'s Constitution modifier + your Charisma modifier + five times your level in this class</text>
+      </trait>
+    <trait>
+        <name>Endless Waltz</name>
+      <text>Immediately after the item makes a slam attack, it can take the Dodge action as a bonus action.</text>
+      </trait>
+    <trait>
+        <name>Immutable Form</name>
+      <text>The item is immune to any spell or effect that would alter its form.</text>
+      </trait>
+    <action>
+        <name>Force-Empowered Slam</name>
+      <text>Melee Weapon Attack: your spell attack modifier to hit, reach 5 ft., one target you can see. 1d10 + your Charisma modifier force damage.</text>
+      </action>
+    <description>
+Source: Unearthed Arcana: 2020 Subclasses Pt2 p. 2</description>
+    <environment></environment>
+    </monster>
+  </compendium>