Add CCM tag to routing tables

[Skarlso]

/kind feature

What this PR does / why we need it:

Add CCM tag to routing tables.

Which issue(s) this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when PR gets merged):
Fixes #3532

Special notes for your reviewer:

Checklist:

• squashed commits
• includes documentation
• adds unit tests
• adds or updates e2e tests

[Ankitasw]

/test pull-cluster-api-provider-aws-e2e

[Ankitasw]

/lgtm
/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: Ankitasw

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• OWNERS [Ankitasw]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[dlipovetsky]

I think this might be incomplete.

Since we already apply the tag to existing subnets, and, as of #3844, we will apply the tag to existing (i.e. override) security groups, then we also want to apply the tag to user-created route tables.

However, this PR does not apply the tag to user-created route tables, only ones created by CAPA.

[Update: This PR is complete. In fact, CAPA should not apply the CCM tag to user-created route tables, unless it also removes the tag on cluster delete. Please see the issue I filed in #3854]

[Skarlso]

Thank you @dlipovetsky! I will create a follow up PR.