* feat: remote write metric task
* chore: pass stanalone task to frontend
* chore: change name to system metric
* fix: add header and rename to export metrics
refactor: move heartbeat configuration into an independent section in config file
* refactor: move heartbeat configuration into an independent section in config file
* feat: add HeartbeatOptions struct
* test: modify corresponding test case
* chore: modify corresponding example file
* chore(prom): rename prometheus(remote storage) to prom-store and promql(HTTP server) to prometheus
* chore: apply clippy suggestions
* chore: adjust format according to rustfmt
* feat(http_body_limit): add initial support for DefaultBodyLimit
* fix: address CR suggestions
* fix: adjust the const for default http body limit
* fix: adjust the toml_str for the test
* fix: address CR suggestions
* fix: body_limit units in example config toml files
* fix: address clippy suggestions
* feat: implement load_options.
* refactor: build by ConfigOptions.
* refactor: init_global_logging by LoggingOptions.
* chore: make clippy happy.
* refactor: use TopLevelOptions push top level options to subcommand.
* test: test TopLevelOptions.
* refactor: push Options in Box.
* refactor: push Options in Box.
* refactor: use let-else and Options.
* docs: Add comments to standalone config example
* docs: Add comments to datanode config example
* docs: Add comments to frontend config example
* docs: Add comments to meta-srv config example
* docs: Use "GB" instead of "GiB"
* docs: Add link to the selector doc
* docs: Fix grammar
* fix: Serialize FrontendOptions to toml
* fix: Serialize DatanodeOptions to toml
* fix: Serialize StandaloneOptions to toml
See https://users.rust-lang.org/t/why-toml-to-string-get-error-valueaftertable/85903/2
* chore!: Rename MetaClientOpts to MetaClientOptions
BREAKING CHANGE: Change the meta_client_opts in the config file to
meta_client_options
* refactor: options and sample configurations
* chore: newline at end of file
* chore: format code
* chore: remove comment and set sample configurations to default values
* chore: use single quoted string in sample configuration files
* feat: frontend instance
* no need to carry column length in `Column` proto
* add more tests
* rebase develop
* create a new variant with already provisioned RecordBatches in Output
* resolve code review comments
* new frontend instance does not connect datanode grpc
* add more tests
* add more tests
* rebase develop
Co-authored-by: luofucong <luofucong@greptime.com>