Add an overload to the LuceneSearchQuery to provide a Lucene Filter

[Shazwazza]

Currently there is an overload specifically on the LuceneSearchQuery that allows passing in a Lucene Query instance to perform a search but it would also be nice to be able to provide a Lucene Filter. For example, this would mean that for Spatial searches we wouldn't have to manually execute the query: https://github.com/Shazwazza/Examine/blob/master/src/Examine.Test/Extensions/SpatialSearch.cs#L100

[dealloc]

I currently integrated spatial queries with this extension methods:

	/// <summary>
	/// Creates a query for results near the given <paramref name="latitude" />, <paramref name="longitude" /> in a radius of <paramref name="distance" />.
	/// </summary>
	/// <remarks>This requires an index of <see cref="Constants.Constants" /> to be present.</remarks>
	public static IBooleanOperation Location(this IQuery query, double latitude, double longitude, double distance)
	{
		if (query is not LuceneSearchQuery luceneQuery)
			throw new InvalidOperationException("Location queries are only supported on Lucene queries");

		var spatialContext = SpatialContext.Geo;
		var grid = new GeohashPrefixTree(spatialContext, 11); // 11 = sub-metre precision for geohash
		var strategy = new RecursivePrefixTreeStrategy(grid, Constants.LOCATION_INDEX_FIELD);

		var args = new SpatialArgs(SpatialOperation.Intersects, spatialContext.MakeCircle(longitude, latitude, DistanceUtils.Dist2Degrees(distance, DistanceUtils.EarthMeanRadiusKilometers)));
		var locationQuery = strategy.MakeQuery(args);

		return luceneQuery.LuceneQuery(locationQuery, BooleanOperation.And);
	}

I currently have the location field on the index as a constant, but it shouldn't be too hard to add a parameter for that, this way I can still treat them like normal Examine queries otherwise.

[nzdev]

I've made a start on filtering and spatial. https://github.com/nzdev/Examine/tree/v4/feature/filter