Set a smaller page limit for bentoml list

[parano]

Description

The default value for list is currently set to 200, which makes the bentoml list very slow for users that have lots of BentoML bundles created. This PR changes this default to 40.

Motivation and Context

How Has This Been Tested?

Types of changes

• Breaking change (fix or feature that would cause existing functionality to change)
• New feature and improvements (non-breaking change which adds/improves functionality)
• Bug fix (non-breaking change which fixes an issue)
• Code Refactoring (internal change which is not user facing)
• Documentation
• Test, CI, or build

Component(s) if applicable

• BentoService (service definition, dependency management, API input/output adapters)
• Model Artifact (model serialization, multi-framework support)
• Model Server (mico-batching, dockerisation, logging, OpenAPI, instruments)
• YataiService gRPC server (model registry, cloud deployment automation)
• YataiService web server (nodejs HTTP server and web UI)
• Internal (BentoML's own configuration, logging, utility, exception handling)
• BentoML CLI

Checklist:

• My code follows the bentoml code style, both ./dev/format.sh and
  ./dev/lint.sh script have passed
  (instructions).
• My change reduces project test coverage and requires unit tests to be added
• I have added unit tests covering my code change
• My change requires a change to the documentation
• I have updated the documentation accordingly

[codecov]

Codecov Report

Merging #887 into master will decrease coverage by 0.00%.
The diff coverage is 50.00%.

@@            Coverage Diff             @@
##           master     #887      +/-   ##
==========================================
- Coverage   61.82%   61.81%   -0.01%     
==========================================
  Files         120      120              
  Lines        7918     7922       +4     
==========================================
+ Hits         4895     4897       +2     
- Misses       3023     3025       +2     

Impacted Files	Coverage Δ
bentoml/yatai/repository/metadata_store.py	66.35% <50.00%> (+0.31%)	⬆️
bentoml/utils/dataframe_util.py	89.90% <0.00%> (-0.49%)	⬇️
bentoml/service.py	85.66% <0.00%> (-0.20%)	⬇️

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