Change order of credential path and read_external_sources and more

[ehdsouza]

This PR does the following:

• Client properties like disable_ssl and url were read only from env, so like rest of the sdk's separated a read_external_sources
• Re-ordeing of fetching credentials from working directory before home dir
• Also removed setting of client properties in the constructor as they now go in the generated service classes

related to https://github.ibm.com/Watson/developer-experience/issues/7521

[codecov[bot]]

Codecov Report

Merging #28 into next will decrease coverage by 0.03%. The diff coverage is 100%.

@@            Coverage Diff             @@
##             next      #28      +/-   ##
==========================================
- Coverage   98.18%   98.15%   -0.04%     
==========================================
  Files          16       16              
  Lines         497      488       -9     
==========================================
- Hits          488      479       -9     
  Misses          9        9

Impacted Files	Coverage Δ
ibm_cloud_sdk_core/base_service.py	97.39% <100%> (-0.15%)	:arrow_down:
ibm_cloud_sdk_core/utils.py	97.97% <100%> (-0.05%)	:arrow_down:
ibm_cloud_sdk_core/__init__.py	100% <100%> (ø)	:arrow_up:

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[ehdsouza]

@padamstx addressed the multi word service name issue.

[watson-github-bot]

:tada: This PR is included in version 1.0.0 :tada:

The release is available on GitHub release

Your semantic-release bot :package::rocket: