Default data directory configurations are confusing

[killme2008]

When deploying a GreptimeDB standalone instance via the Helm chart (https://greptime.com/blogs/2023-12-12-helm-chart), the data_home is set to /data/greptimedb.

However, the logging directory, configured as "./greptimedb_data/logs", resides outside of this data_home.

[storage]
data_home = "/data/greptimedb/"
type = "S3"
name = ""
bucket = "test-bucket"
root = "dennis_standalone"
endpoint = ""
region = "ap-southeast-1"
enable_virtual_host_style = false
providers = []

[logging]
dir = "./greptimedb_data/logs"
log_format = "text"
max_log_files = 720
append_stdout = true
enable_otlp_tracing = false

The rationale for this discrepancy is unexpected and unclear.

@zyy17

I think we should take care all of the default configurations in docker images and helmchart and make sure they are using the consistent directories.