Accommodate comma-separated config values

There's no way to provide comma-separated config values through the configuration argument.

For example, I want to specify a list of services via the SERVICES config variable (e.g., SERVICES=s3,ec2,secretsmanager,ecs,iam,sts,fis). However, the configuration parsing code naively splits the provided string on commas:
https://github.com/localstack/localstack-dagger-module/blob/6e2683e20e54e7ceab130ebe2abed050b6670ed2/src/localstack/main.py#L47-L52

As such, when specifying configuration as follows, ec2 is recognized as a separate config variable rather than another service in the list of services that comprise the value for the SERVICES config variable:

dag.Localstack().Start(dag.LocalstackStartOpts{
  Configuration: "SERVICES=s3,ec2,secretsmanager,ecs,iam,sts,fis"
})

There are a few solutions to this:

1. use a non-comma delimiter to distinguish configuration key-value pairs (e.g., use ; as the delimiter: "SERVICES=s3,ec2,secretsmanager;AWS_DEFAULT_REGION=east-us-1")
2. accommodate escaped quotes (e.g., "SERVICES=\"s3,ec2,secretsmanager\",AWS_DEFAULT_REGION=east-us-1")

Start by reading the configuration parsing code in src/localstack/main.py at lines 47-52 and trace how the configuration argument is split. Compare the proposed delimiter and escaping approaches, then check the repository's existing tests or test commands. Done means comma-separated values remain part of one configuration value while separate configuration entries still parse correctly.