feat: support init SDK with custom configuration

[zhu-xiaowei]

• PR title and description conform to Pull Request guidelines.

Description of changes:

1. support init SDK with custom configuration
2. support add global attribute in configuration
3. compatible with amplifyconfiguration.json file

How did you test these changes?
added test case for support configure amplify multiple times.

Documentation update required?

• No
• Yes (Please include a PR link for the documentation update)

General Checklist

• Added Unit Tests

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 97.43590% with 3 lines in your changes missing coverage. Please review.

Project coverage is 87.93%. Comparing base (eff7fe2) to head (979dfaf).
Report is 10 commits behind head on main.

Files with missing lines	Patch %	Lines
...aws/solution/clickstream/ClickstreamAnalytics.java	96.15%	2 Missing ⚠️
...aws/solution/clickstream/AWSClickstreamPlugin.java	97.43%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##               main      #75      +/-   ##
============================================
+ Coverage     86.70%   87.93%   +1.23%     
- Complexity      468      488      +20     
============================================
  Files            42       40       -2     
  Lines          1707     1716       +9     
  Branches        156      171      +15     
============================================
+ Hits           1480     1509      +29     
+ Misses          150      140      -10     
+ Partials         77       67      -10     

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