refactor: Refactor traffic graph display algorithm

Created by: leoendless

Signed-off-by: leoliu leoliu@yunify.com

What type of PR is this?

/kind bug

What this PR does / why we need it:

Remove workaround SVG CSS styles.

Calculate edge position data with source node position and target node position.

Which issue(s) this PR fixes:

Fixes #

Special notes for reviewers:

Additional documentation, usage docs, etc.: