[WIP] [JIRA] new method get_issue_status_changelog + docs + example +small improvement get_issue

[gkowalc]

This PR adds:

• new method for jira get_issue_status_changelog to return history of status changes of the given issue key + related docs and examples
• In addition to above new method I have added small improvement to JIRA get_issue method to include expand flag for the params - https://github.com/atlassian-api/atlassian-python-api/issues/1354

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 16.66667% with 10 lines in your changes are missing coverage. Please review.

Project coverage is 34.14%. Comparing base (d4ef596) to head (6a83b0b).

Files	Patch %	Lines
atlassian/jira.py	16.66%	10 Missing :warning:

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Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #1357 +/- ## ========================================== - Coverage 34.15% 34.14% -0.02% ========================================== Files 46 46 Lines 8437 8444 +7 Branches 1188 1190 +2 ========================================== + Hits 2882 2883 +1 - Misses 5440 5446 +6 Partials 115 115 ```

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[gkowalc]

thx for the revierw @Spacetown, let me refactor the code a bit accordign to your suggestions and send a new PR.

[gonchik]

@gkowalc thanks for update