feat: add context manager support for bentoml.client

[y1450]

• implments __enter__,__exit__,__aenter__and __aexit__

A dummy implementation is added to support to context protocol as it is required for the 'with' statement.

The implementation of exit method is empty as client does not have any persistent connection, each api call is processed in a separate aio.http session.

What does this PR address?

Fixes #(issue)

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[y1450]

I could not find any existing test cases for initial PR (#3028).
One can add tests for clean up and setup, However going through the existing code, I could not infer what exactly need to be cleanup.
My first idea was HTTP connection, but it is already managed through session which is created on each call.

BentoML/src/bentoml/client.py

Line 163 in 931dedc

async with aiohttp.ClientSession(self.server_url) as sess:

As a testcase I tried this but I am not sure whether it is good test?

from bentoml.client import Client
import numpy as np
client = Client.from_url("http://localhost:3000")
client.classify(np.array([[4.9, 3.0, 1.4, 0.2]]))
with Client.from_url("http://localhost:3000") as cl:
    print(cl)
# should this give exception or not?    
# currently, it executes without any exception.
cl.classify(np.array([[4.9, 3.0, 1.4, 0.2]]))  

[aarnphm]

With one minor comment. Otherwise, it is pretty straightforward.

Right now, we don't have a test for our client, but ideally, the client should be used for our tests feature, which is under construction 🚧 from #2968.

I'm also thinking of moving this to #3280 as I refactor and add gRPC support for bentoml.client.

[codecov]

Codecov Report

Merging #3402 (cc76526) into main (75daa5a) will decrease coverage by 0.03%.
The diff coverage is 0.00%.

@@            Coverage Diff             @@
##             main    #3402      +/-   ##
==========================================
- Coverage   33.13%   33.10%   -0.04%     
==========================================
  Files         132      132              
  Lines       10679    10689      +10     
  Branches     1777     1778       +1     
==========================================
  Hits         3539     3539              
- Misses       6900     6910      +10     
  Partials      240      240              

Impacted Files	Coverage Δ
src/bentoml/client.py	0.00% <0.00%> (ø)

[aarnphm]

Thanks for the contritbutions.