CI: refactor how e2e tests are run in github actions

[MSalopek]

At present e2e tests are part of the Automated tests job which runs unit-, integration- and e2e-tests sequentially.

It would be beneficial to split e2e tests from unit- and integration-tests to simplify the the result reporting.

e2e happy path should run separately from other tests and have its own workflow file. The job's name should be e2e-happy-path and it should run on every push/commit.

Sources:

• https://github.com/cosmos/interchain-security/blob/main/.github/workflows/automated-tests.yml

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Additionally, the manual-e2e and nightly-e2e test runs should be refactored to include multiple tests runs instead of running all e2e test scenarios sequentially.

e.g. the jobs can be changed to include multiple job sections:

jobs:
  test-happy-path:
    runs-on: ubuntu-latest
    timeout-minutes: 60
    steps:
      - uses: actions/setup-go@v4
        with:
          go-version: "1.20"
      - uses: actions/checkout@v3
      - name: happy pathE2E tests
        run: make test-e2e-short
    multiconsumer-path:
      runs-on: ubuntu-latest
      timeout-minutes: 60
      steps:
        - uses: actions/setup-go@v4
          with:
            go-version: "1.20"
        - uses: actions/checkout@v3
        - name: happy pathE2E tests
          run: make test-e2e-multi-consumer

Most of the logic regarding the test starts existis in main.go which the Makefile uses to start the tests. The Makefile and main.go flags may need to be extended to support running the distinct paths individually.

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Note:

Check the comments in #1179 and consider splitting happy path into 2 smaller jobs - one with normal downtime and the other with soft opt-out/throttling downtime. That will require changes in the testing suite.