feat: enable caching when using object store

[e1ijah1]

I hereby agree to the terms of the GreptimeDB CLA

What's changed and what's your intention?

Enable cache layer by default when using s3/OSS storage in the GreptimeDB.

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)

closes #918

[codecov]

Codecov Report

Merging #928 (b35d8d3) into develop (9a30ba0) will decrease coverage by 0.55%.
The diff coverage is 60.90%.

@@             Coverage Diff             @@
##           develop     #928      +/-   ##
===========================================
- Coverage    86.14%   85.59%   -0.55%     
===========================================
  Files          434      445      +11     
  Lines        58411    59936    +1525     
===========================================
+ Hits         50316    51305     +989     
- Misses        8095     8631     +536     

Flag	Coverage Δ
rust	85.59% <60.90%> (-0.55%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
src/datanode/src/datanode.rs	57.62% <ø> (ø)
src/datanode/src/instance.rs	41.56% <0.00%> (-16.21%)	⬇️
src/object-store/src/lib.rs	100.00% <ø> (ø)
tests-integration/src/test_util.rs	79.47% <0.00%> (-9.10%)	⬇️
src/object-store/src/cache_policy.rs	90.54% <90.54%> (ø)
src/object-store/src/test_util.rs	0.00% <0.00%> (-100.00%)	⬇️
src/servers/src/query_handler/sql.rs	36.53% <0.00%> (-24.76%)	⬇️
src/frontend/src/instance/standalone.rs	61.70% <0.00%> (-21.16%)	⬇️
src/common/error/src/ext.rs	75.28% <0.00%> (-20.44%)	⬇️
src/servers/src/http/handler.rs	47.82% <0.00%> (-18.85%)	⬇️
... and 112 more

Help us with your feedback. Take ten seconds to tell us how you rate us. Have a feature suggestion? Share it here.

[killme2008]

Looks great. It's a pity that opendal doesn't support cache eviction by disk or memory quota, the cached objects may consume too much memory or disk. But I think it's okay right now, we still have to design and impl a more powerful cache layer for object storages.

[waynexia]

I would prefer to leave memory to a more fine-grained cache manager like page cache or query cache. They are much more expensive than disks and may not provide a comparable performance improvement when used to cache the entire file.

[killme2008]

LGTM

[waynexia]

Looking great 👍 Thanks @e1ijah1, I only left a nit-picking style comment.