Add support for retry-after header

[tellet-q]

Add support for following responses from Qdrant:

Rate limiter hit for gRPC: qdrant/qdrant#6072

Usage example for strict mode ("read_rate_limit": 60, "write_rate_limit": 60):

package main

import (
	"context"
	"fmt"

	"github.com/qdrant/go-client/qdrant"
)

func hitWriteRateLimit(qClient *qdrant.Client) {
	fmt.Println("start hit_rate_limit")

	for i := 0; i < 500; i++ {
		_, err := qClient.Upsert(context.Background(), &qdrant.UpsertPoints{
			CollectionName: "benchmark",
			Points: []*qdrant.PointStruct{
				{
					Id:      qdrant.NewIDNum(uint64(i)),
					Vectors: qdrant.NewVectors(0.05, 0.61, 0.76, 0.74),
				},
			},
		})
		if err != nil {
			var resourceErr *qdrant.QdrantResourceExhaustedError
			if errors.As(err, &resourceErr) {
				fmt.Printf("hit_rate_limit! %s\nretry after: %d seconds\n", resourceErr.Error(), resourceErr.RetryAfterS)
				break
			}
			panic(err) // This runs only if the error is not QdrantResourceExhaustedError
		}
	}
	fmt.Println("done hit_rate_limit")
}

func collectionExists(qClient *qdrant.Client) {
	exists, err := qClient.CollectionExists(context.Background(), "benchmark")
	if err != nil {
		panic(err)
	}
	fmt.Println("Collection exists: ", exists)
}

func main() {
	client, err := qdrant.NewClient(&qdrant.Config{
		Host:                   "localhost",
		Port:                   6334,
		SkipCompatibilityCheck: false,
	})
	if err != nil {
		panic(err)
	}
	collectionExists(client)
	hitWriteRateLimit(client)
}