Adding VPN options for IKE version and IKE split connections

[Pearl1594]

Description

IKE version allows selecting ike (autoselect), ikev1, or ikev2.
Split connections gives an option of separating the first right subnet from the rest, and kicking out individual statements for each right subnet for better cross-compatibility.

Backported from PR: #4137
update per PR suggestion

Fixes #3138

Types of changes

• Breaking change (fix or feature that would cause existing functionality to change)
• New feature (non-breaking change which adds functionality)
• Bug fix (non-breaking change which fixes an issue)
• Enhancement (improves an existing feature and functionality)
• Cleanup (Code refactoring and cleanup, that may add test cases)

Feature/Enhancement Scale or Bug Severity

Feature/Enhancement Scale

• Major
• Minor

Bug Severity

• BLOCKER
• Critical
• Major
• Minor
• Trivial

Screenshots (if appropriate):

How Has This Been Tested?