Reorganize test folder: Move e2e support files into a separate folder (#15899)

frontend/test/__runner__/run_cypress_tests.js

frontend/test/__support__/e2e/commands.js

frontend/test/__support__/e2e/cypress-plugins.js

frontend/test/__support__/e2e/cypress-snapshots.json

frontend/test/__support__/e2e/cypress.js

frontend/test/__support__/e2e/cypress.json

frontend/test/__support__/e2e/cypress_data.js

frontend/test/__support__/e2e/cypress_sample_dataset.js

frontend/test/cypress-snapshots.json

frontend/test/metabase-db/mongo/add.cy.spec.js

frontend/test/metabase-db/mongo/query.cy.spec.js

frontend/test/metabase-db/mysql/add.cy.spec.js

frontend/test/metabase-db/mysql/custom-column.cy.spec.js

frontend/test/metabase-db/mysql/query.cy.spec.js

frontend/test/metabase-db/postgres/add.cy.spec.js

frontend/test/metabase-db/postgres/custom-column.cy.spec.js

frontend/test/metabase-db/postgres/native.cy.spec.js

frontend/test/metabase-db/postgres/permissions.cy.spec.js

frontend/test/metabase-db/postgres/query.cy.spec.js

frontend/test/metabase-db/postgres/sandboxes.cy.spec.js