Add docs for usage of Jobs SDK

[siri-varma]

Description

Add documentation for Jobs SDK

Issue reference

We strive to have all PR being opened based on an issue, where the problem or feature have been discussed prior to implementation.

Please reference the issue this PR will close: #1324

Checklist

Please make sure you've completed the relevant tasks for this PR, out of the following list:

• Code compiles correctly
• Created/updated tests
• Extended the documentation

[siri-varma]

@dapr/approvers-java-sdk @cicoyle @artur-ciocanu @salaboy Let me know your thoughts on this PR

[siri-varma]

/assign

[siri-varma]

@dapr/approvers-java-sdk @artur-ciocanu @cicoyle @salaboy Could you folks look at this PR too when you get a chance ? Thank you.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 77.13%. Comparing base (d759c53) to head (cac826e).
Report is 134 commits behind head on master.

Additional details and impacted files

@@             Coverage Diff              @@
##             master    #1323      +/-   ##
============================================
+ Coverage     76.91%   77.13%   +0.21%     
- Complexity     1592     1728     +136     
============================================
  Files           145      200      +55     
  Lines          4843     5291     +448     
  Branches        562      579      +17     
============================================
+ Hits           3725     4081     +356     
- Misses          821      897      +76     
- Partials        297      313      +16     

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[artur-ciocanu]

LGTM