Added new liquibase.duplicateFileMode setting

[nvoxland]

Impact

• Bug fix (non-breaking change which fixes expected existing functionality)
• Enhancement/New feature (adds functionality without impacting existing logic)
• Breaking change (fix or feature that would cause existing functionality to change)

Description

Currently, when the same path is found in multiple locations liquibase fails with an error.

This PR adds a new liquibase.duplicateFileMode global setting which defaults to "ERROR" but can also be set to "WARN".

Things to be aware of

• Existing behavior of "ERROR" logic is still the default.
• Refactored some usages of openStreams that duplicated the logic in openStream to just use openStream in order to take advantage of this new behavior.
• Searched the code for usages of openStream vs. openStreams and addressed all I found that should be updated

Things to worry about

• Nothing

[github-actions]

Unit Test Results

  4 548 files  +   379    4 548 suites  +379   32m 14s ⏱️ + 5m 4s
  4 523 tests +       1    4 309 ✔️ +     77     214 💤  -   30  0 ❌ ±0 
53 556 runs  +4 474  48 548 ✔️ +4 080  5 008 💤 +440  0 ❌ ±0 

Results for commit 9e1ce2a. ± Comparison against base commit e8c6019.

♻️ This comment has been updated with latest results.

[kataggart]

note: if duplicate is found, first one is processed (need to define in docs what "first" is); please keep default as ERROR

[FBurguer]

Now when you duplicateFileMode=WARN you get msg explainng that liquibase found 2 changelogs with the same name but continues working with the "first" changelog it founds.
Both values work as expected and the default value is ERROR like in the description of the PR.

Test Environment:
OS: Windows 10
MySQL Docker Container v8.0.27
Java 8