WIP: Improve frontend code structure

[sultan-duisenbay]

We are creating many components, so it's time to structurize those elements.

Moved al routers to navigation dir, all grid components to grid dir, all dashboard components to dashboard dir and group related components to group dir.

[google-oss-prow[bot]]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: sultan-duisenbay

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[google-oss-prow[bot]]

@sultan-duisenbay: The following test failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
test-testgrid-npm	b25029d56be69f9bd87a3f2598c772c926d5e2d0	link	true	/test test-testgrid-npm

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[michelle192837]

This is great, thanks! I think it should be separated from the other commit though, or indicate this is blocked by another PR.