Make RuntimeEnvBuilder rather than RuntimeConfig

[alamb]

Is your feature request related to a problem or challenge?

@theirix added a very nice API in #12151 to simplify RuntimeEnv construction.

However, @comphead pointed out https://github.com/apache/datafusion/pull/12151/files#r1730134993 the names are now somewhat strange that you get a runtime_env when creating a RuntimeConfig object

            let runtime_env = RuntimeConfig::new()
                .with_memory_pool(Arc::new(GreedyMemoryPool::new(pool_size)))
                .build();

Describe the solution you'd like

I think a more standard pattern would be of RuntimeConfig was called RuntimeEnvBuilder

Then the example would look like

            let runtime_env = RuntimeEnvBuilder::new()
                .with_memory_pool(Arc::new(GreedyMemoryPool::new(pool_size)))
                .build();

Describe alternatives you've considered

I suggest:

1. Rename RuntimeEnvBuilder to RuntimeConfig
2. Leave a type alias type RuntimeConfig = RuntimeEnvBuilder to ease upgrades (maybe the typedef could be deprecated with a message to use RuntimeEnvBuilder)

Additional context

No response

[devanbenz]

take