Added Signal Handlers to the backend for shutting down the process and adding restart.test.js

[shivaahir158]

Motivate of the pull request

• To address an existing issue. If so, please provide a link to the issue:
• Breaking new feature. If so, please describe details in the description part.

Describe the technical details -

1. Adding signal handlers for shutting down the process to the backend (restapi_server.py).
2. Added restart.test.js e2e test.

What is currently done? (Provide issue link if applicable)

What does this pull request change?

Which part of the code base require a change

• Frontend:
• Backend: restapi_server.py
• Library: <Specify the library name, e.g. npm packages>
• Plug-in: <Specify the plugin name, e.g. Webpack, jtest>
• Documentation
• Regression tests: e2e/restart.test.js
• Continuous Integration (CI) scripts

Impact of the pull request

• Require a change on Quality of Results (QoR)
• Break backward-compatibility. If so, please list who may be influenced.

[codecov]

Codecov Report

Attention: Patch coverage is 42.85714% with 8 lines in your changes missing coverage. Please review.

Project coverage is 68.78%. Comparing base (f7aa4b6) to head (90688b6).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
backend/restapi_server.py	42.85%	8 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #268      +/-   ##
==========================================
- Coverage   68.83%   68.78%   -0.05%     
==========================================
  Files         110      110              
  Lines        9022     9035      +13     
  Branches      402      402              
==========================================
+ Hits         6210     6215       +5     
- Misses       2812     2820       +8     

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[shivaahir158]

@NadeemYaseen , please check the changes pushed we discussed for restart.test.js.

[NadeemYaseen]

@NadeemYaseen , please check the changes pushed we discussed for restart.test.js.

The current test works locally on Linux. The use of kill command ensure that we are killing the backend process.