Changed IconButton to KRouterLink

[BabyElias]

Summary

Updated IconButton to use KComponents (KRouterLink, KIcon & KIconButton) instead.

Description of the change(s) you made

learningequality/kolibri-design-system#219

Screenshots (if applicable)

The icons that have been changed

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Reviewer guidance

How can a reviewer test these changes?

This is just a trial PR to confirm that I am headed in the right direction or not.
If this pull request is accepted and merged, I plan to submit additional pull requests addressing other issue with more extensive changes. The current pull request contains only minor modifications related to that issue.

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Contributor's Checklist

Testing:

• Code is clean and well-commented
• Contributor has fully tested the PR manually
• If there are any front-end changes, before/after screenshots are included

Reviewer's Checklist

This section is for reviewers to fill out.

• Automated test coverage is satisfactory
• PR is fully functional
• PR has been tested for accessibility regressions
• External dependency files were updated if necessary (yarn and pip)
• Documentation is updated
• Contributor is in AUTHORS.md

[nucleogenesis]

Just a couple of changes in the StagingTreePage/index.vue updates here.

Overall this is the exact right direction! Thanks so much @BabyElias for this submission!

[BabyElias]

Thank you so much for your feedback!
Done with the required changes. If this PR is good to go, then I'll create separate PRs for changes at other places to ensure that checks are done for each change properly.

[nucleogenesis]

Thanks @BabyElias I've tested this locally and all looks good! Feel free to tag me for review on any follow-up issues you create along these lines.