Add FullTextTable class attribute & FullTextIndexed property attribute for easy FTS indexing

[risukun]

Add FullTextTable class attribute & FullTextIndexed property attribute for easy FTS indexing

Add simple attribute support for full text indexing of a subset of columns in table as well as support to change the default tokenizer behavior [for the table. Porting a change that I did in a copy of SQLite.cs for a UWP Japanese dictionary app ~9 years ago that I'm now trying to port to MAUI. Updated to include detecting FTS column changes and rebuilding the index when the column list changes. Added a bunch of unit tests to cover the functionality and confirmed the existing tests are all passing on Win11.

Note that this PR does NOT port custom tokenizer support that I also had added in order to use a Japanese word breaker, but I can work around that with pre-breaking using a .NET Japanese language model library as long as I can at least use the "unicode61" tokenizer instead of the default "simple" one that clobbers most Unicode characters.

Example usage:

	**[FullTextTable]**
	public class Article
	{
		[PrimaryKey, AutoIncrement]
		public int Id { get; set; }

		**[FullTextIndexed]**
		public string Title { get; set; }

		**[FullTextIndexed]**
		public string Content { get; set; }
		public string Author { get; set; }
		public DateTime PublishDate { get; set; }
	}

	**[FullTextTable("JapaneseText_FT", "unicode61")]**
	public class JapaneseText
	{
		[PrimaryKey, AutoIncrement]
		public int Id { get; set; }

		**[FullTextIndexed]**
		public string Text { get; set; }

		public string Notes { get; set; }
	}
	
	var query = "SELECT * FROM Article WHERE Id IN (SELECT docid FROM Article_FT WHERE Article_FT MATCH 'programming')";
	var results = db.Query<Article>(query);