Allow bootstrap_servers argument usage without quotes

[g-despot]

When creating a stream, the bootstrap_servers argument needs to be specified with quotes around it:

stream = MemgraphKafkaStream(
    name="ratings_stream",
    topics=["ratings"],
    transform="movielens.rating",
    bootstrap_servers="'kafka:9092'",
)
memgraph.create_stream(stream)

This can sometimes be misleading and users will maybe pass a plain string without the additional quotes. Both options need to be handled in the background and adjusted to the proper Cypher syntax.

Additionally, passing multiple bootstrap servers should be allowed in the form of a list of strings:

stream = MemgraphKafkaStream(
    name="ratings_stream",
    topics=["ratings"],
    transform="movielens.rating",
    bootstrap_servers=["kafka:9092", "kafka:9093"],
)
memgraph.create_stream(stream)