Add tag to XML file when edited DayOne entry and is searchable afterward

[jonakeys]

Checklist

• I have read the contributing doc.
• I have included a link to the relevant issue number.
• I have checked to ensure there aren't other open pull requests
  for the same issue.
• I have written new tests for these changes, as needed.

Fixes #1049
When DayOne entry is edited and a tag is added, jrnl now adds this tags correctly to the XML file.
Also included a BDD test for DayOne and different configs.

[jonakeys]

Problem during regression tests..

[jonakeys]

Now working with all tests. Had to fix the random order in which tags are saved to prevent seeing it as modified while the items stayed the same.

[wren]

Looks good. Thank you!