[GOBBLIN-1674] : Add an option in gobblin.sh to specify whether to run the Gobblin job in background or not

[bharos]

Dear Gobblin maintainers,

Please accept this PR. I understand that it will not be reviewed until I have checked off all the steps below!

JIRA

• My PR addresses the following Gobblin JIRA issues and references them in the PR title. For example, "[GOBBLIN-XXX] My Gobblin PR"
  • https://issues.apache.org/jira/browse/GOBBLIN-XXX

Description

• Here are some details about my PR, including screenshots (if applicable):
  Currently, the command uses 'nohup' and '&' which always makes it run in background.
  This makes it inconvenient in use-cases that need to do some action after the run is
  completed (like curling for some logs). Hence, providing an option to choose whether
  to run in background or not.

Tests

• My PR adds the following unit tests OR does not need testing for this extremely good reason:
  Tested in local environment with the new flag, unit tests Not applicable.

Commits

• My commits all reference JIRA issues in their subject lines, and I have squashed multiple commits if they address the same issue. In addition, my commits follow the guidelines from "How to write a good git commit message":
  1. Subject is separated from body by a blank line
  2. Subject is limited to 50 characters
  3. Subject does not end with a period
  4. Subject uses the imperative mood ("add", not "adding")
  5. Body wraps at 72 characters
  6. Body explains "what" and "why", not "how"

[abti]

+1 It looks good to me.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 46.68%. Comparing base (9ce1e65) to head (a1b3d3f).
⚠️ Report is 583 commits behind head on master.

Additional details and impacted files

@@             Coverage Diff              @@
##             master    #3534      +/-   ##
============================================
- Coverage     46.69%   46.68%   -0.01%     
- Complexity    10432    10436       +4     
============================================
  Files          2083     2083              
  Lines         81516    81516              
  Branches       9100     9100              
============================================
- Hits          38061    38056       -5     
- Misses        39944    39946       +2     
- Partials       3511     3514       +3     

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[Will-Lo]

@bharos Could you rebase from master? It conflicts with the previous changes that you've made