[Refactor] Combine e2e labels into one label

[vankichi]

Is your feature request related to a problem? Please describe.:

Now, the vdaas/vald repository executes the e2e test on PR by adding e2e-related labels ( actions/e2e-chaos, actions/e2e-deploy, etc.)
Given Actions' inability to trigger workflows based on specific label events, we're evaluating whether to run corresponding E2E tests within the label assignment workflow by parsing the label name.

With the above, workflows unrelated to labels will also be executed once (and then skipped), but this makes it difficult to see the operation status of actions, so we would like to improve this.

Describe the solution you'd like:

Modified to execute only necessary E2E

Describe alternatives you've considered:

There are several ways to do this (labeling, using chatops, etc.), so we would like to decide on a policy through discussion and then implement it.