Implements the rating system.
Shipwreck Lagoon tracks theoretically work, but there's currently no way of testing them.
There is a hack to make the ranked pods section of the blaster party board work. Don't know if that'll cause any issues (but I don't think so).
SQLite database schema changes:
```sql
CREATE TABLE "RatingRanks" (
"Id" INTEGER NOT NULL,
"CategoryID" INTEGER NOT NULL,
"RatedEntityID" INTEGER,
"RatedUserID" TEXT,
"Rank" INTEGER NOT NULL,
"RatingAverage" REAL NOT NULL,
"UpdateDate" TEXT NOT NULL,
CONSTRAINT "PK_RatingRanks" PRIMARY KEY("Id" AUTOINCREMENT)
);
CREATE TABLE "Ratings" (
"Id" INTEGER NOT NULL,
"VikingId" INTEGER NOT NULL,
"RankId" INTEGER NOT NULL,
"Value" INTEGER NOT NULL,
"Date" TEXT NOT NULL,
CONSTRAINT "FK_Ratings_RatingRanks_RankId" FOREIGN KEY("RankId") REFERENCES "RatingRanks"("Id") ON DELETE CASCADE,
CONSTRAINT "PK_Ratings" PRIMARY KEY("Id" AUTOINCREMENT),
CONSTRAINT "FK_Ratings_Vikings_VikingId" FOREIGN KEY("VikingId") REFERENCES "Vikings"("Id") ON DELETE CASCADE
);
```
---------
Co-authored-by: Robert Paciorek <robert@opcode.eu.org>
