feat: add walconfig dir back

[shoothzj]

I hereby agree to the terms of the GreptimeDB CLA

What's changed and what's your intention?

PLEASE DO NOT LEAVE THIS EMPTY !!!

Add Wal dir config back.

Checklist

• I have written the necessary rustdoc comments.
• I have added the necessary unit tests and integration tests.

Refer to a related PR or issue link (optional)

#2312

[killme2008]

Cool! Thank u for your contribution.

Looks like we need to use this parameter in build_log_store:

greptimedb/src/datanode/src/datanode.rs

Line 368 in 6e87ac0

async fn build_log_store(opts: &DatanodeOptions) -> Result<Arc<RaftEngineLogStore>> {

If it is presented(not none), we use it instead of format!("{}{WAL_DIR}", data_home).

[killme2008]

@shoothzj Looks like there is a code format issue.

Please run the cargo fmt and cargo clippy --workspace --all-targets -- -D commands to ensure no code format issues or clippy warnings before committing.

Or you can use a post-commit hook, see the contributing guide:
https://github.com/GreptimeTeam/greptimedb/blob/develop/CONTRIBUTING.md#before-pr

[shoothzj]

@killme2008 When I run the cargo clippy --workspace --all-targets -- -D on my macos. It shows

error: failed to run `rustc` to learn about target-specific information

Caused by:
  process didn't exit successfully: `/Users/akka/.rustup/toolchains/nightly-2023-08-07-aarch64-apple-darwin/bin/clippy-driver /Users/akka/.rustup/toolchains/nightly-2023-08-07-aarch64-apple-darwin/bin/rustc - --crate-name ___ --print=file-names '-Wclippy::print_stdout' '-Wclippy::print_stderr' '-Wclippy::implicit_clone' '-Aclippy::needless_pass_by_ref_mut' --crate-type bin --crate-type rlib --crate-type dylib --crate-type cdylib --crate-type staticlib --crate-type proc-macro --print=sysroot --print=split-debuginfo --print=crate-name --print=cfg` (exit status: 1)
  --- stderr
  error: multiple input filenames provided (first two filenames are `-` and `feature="cargo-clippy"`)

[codecov]

Codecov Report

Merging #2606 (dae86a5) into develop (6e87ac0) will decrease coverage by 0.37%.
Report is 1 commits behind head on develop.
The diff coverage is 85.71%.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #2606      +/-   ##
===========================================
- Coverage    85.33%   84.97%   -0.37%     
===========================================
  Files          737      737              
  Lines       118030   118042      +12     
===========================================
- Hits        100724   100306     -418     
- Misses       17306    17736     +430     

[killme2008]

@shoothzj Have you installed clippy? https://github.com/rust-lang/rust-clippy

[killme2008]

Sorry, my mistake. The full command is cargo clippy --workspace --all-targets -- -D warnings.

[killme2008]

LGTM. Thank u.

[waynexia]

Others LGTM

[shoothzj]

add docs PR GreptimeTeam/docs#651.
@killme2008 @sunng87 I think this PR can be merged. Thanks :)