Optimize Cypress yarn scripts

Currently, to launch the Cypress test runner GUI, in frontend/package.json we have:

"test-cypress": "cd packages/integration-tests-cypress && cypress open ...",
 "test-cypress-devconsole": "cd packages/dev-console/integration-tests && cypress open...",
 "test-cypress-olm": "cd packages/operator-lifecycle-manager/integration-tests-cypress && cypress open ..."

We want one "test-cypress" command which takes a 'pkg' parameter, values of 'olm', 'devconsole', 'console'(default).

This will cd to correct dir and use any other config settings needed for olm cypress testing:

yarn run test-cypress olm

We also have cypress headless yarn scripts:

"test-cypress-headless": "yarn run test-cypress-console-headless && yarn run test-cypress-devconsole-headless && yarn run test-cypress-olm-headless",
 "test-cypress-console-headless": "cd packages/integration-tests-cypress && cypress run ...",
 "test-cypress-devconsole-headless": "cd packages/dev-console/integration-tests && cypress run --spec \"features/project-creation.feature\"
 "test-cypress-olm-headless": "cd packages/operator-lifecycle-manager/integration-tests-cypress && cypress run --config-file cypress-olm.json"

We want to extend the aforementioned `test-cypress` command to take a '--headless' parmeter which will run the pkg in --headless mode:

"yarn run test-cypress olm --headless"

This would replace the individual "test-cypress-<pkg>-headless" yarn scripts (if possible).

test-cypress.sh will need to be updated accordingly!