add new .env.example to packages/create-cloudflare project

packages/create-cloudflare/.env.example

@@ -0,0 +1,9 @@
+# rename/copy this file to .env to control the local c3 process
+# (currently used only to control the behavior of the e2es locally)
+
+# CLOUDFLARE_API_TOKEN=?  # the cloudflare api token needed for the deployment of projects
+# CLOUDFLARE_ACCOUNT_ID=? # the id of the account needed for the deployment of projects
+# FRAMEWORK_CLI_TO_TEST=? # the name of the cli of the _only_ framework to run e2e tests for
+# E2E_PROJECT_PATH=?      # the path were to build the projects (for easier debugging, instead of having to find the tmpdir)
+# E2E_RETRIES=0           # the number of retries for framework e2e tests
+# E2E_NO_DEPLOY=true      # flag to skip the deployment step in the e2es (for easier debugging, where the deployment is not relevant to current changes)