infinitepush: drop the `--create` flag to push command The extension added a `--create` flag for creating a new bookmark on the bundlestore. This patch changes the bahviour to create a bookmark if it does not exists and removes the requirement of the `--create` and then drop the logic around the `--create` flag. Tests are changed to drop the usage of `--create` flag. Differential Revision: https://phab.mercurial-scm.org/D2107