Disambiguate files on import

[jonenst]

Please check if the PR fulfills these requirements

• [x] The commit message follows our guidelines
• [ ] Tests for the changes have been added (for bug fixes / features)
• [ ] Docs have been added / updated (for bug fixes / features)

Does this PR already have an issue describing the problem?

https://github.com/powsybl/powsybl-core/issues/989

3082

2959

others...

What kind of change does this PR introduce? bug fix

What is the current behavior?

$ itools convert-network --input-file foo.xiidm # will wrongly use foo.xml from cgmes if it exists

What is the new behavior (if this is a feature change)? always use the file specified by the user in the command line

Does this PR introduce a breaking change or deprecate an API?

• [ ] Yes
• [x] No

[sonarcloud[bot]]

Quality Gate failed

Failed conditions
59.5% Coverage on New Code (required ≥ 80%)

See analysis details on SonarCloud

[jonenst]

Need more tests

[flo-dup]

Replaced by #3102