Extract the external curve loop query to its own method

[vietle-bh]

NOTE: Depends on

Issues addressed by this PR

Closes #1496

Extracted the external curve loop query to its own method

Test files

I simply cut & pasted the relevant code to a new file, so hopefully just code review will be enough!

Changelog

Additional comments

[vietle-bh]

@BHoMBot check compliance @BHoMBot check core @BHoMBot check null-handling @BHoMBot check serialisation @BHoMBot check project-compliance @BHoMBot check versioning @BHoMBot check installer

[bhombot-ci[bot]]

@vietle-bh to confirm, the following actions are now queued: - check `code-compliance` - check `documentation-compliance` - check `project-compliance` - check `branch-compliance` - check `dataset-compliance` - check `copyright-compliance` - check `core` - check `null-handling` - check `serialisation` - check `project-compliance` - check `versioning` - check `installer` There are 8 requests in the queue ahead of you.

[vietle-bh]

@BHoMBot check versioning @BHoMBot check installer

[bhombot-ci[bot]]

@vietle-bh to confirm, the following actions are now queued: - check `versioning` - check `installer` There are 11 requests in the queue ahead of you.

[vietle-bh]

@BHoMBot check versioning @BHoMBot check installer

[bhombot-ci[bot]]

@vietle-bh to confirm, the following actions are now queued: - check `versioning` - check `installer` There are 14 requests in the queue ahead of you.

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[pawelbaran]

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