* Reuse ACMEv1 accounts for ACMEv2
* Correct behavior
* add unit tests
* add _find_all_inner to comply with interface
* acme-staging-v01 --> acme-staging
* only create symlink to previous account if there is one there
* recurse on server path
* update tests and change internal use of load to use server_path
* fail gracefully on corrupted account file by returning [] when rmdir fails
* only reuse accounts in staging for now
* Add post wrapper to automatically add acme_version
* Add uri to authzr.
* Only add kid when account is set.
* Add content_type when downloading certificate.
* Only save new_authz URL when it exists.
* Handle combinations in ACMEv1 and ACMEv2.
* Add tests for ACMEv2 "combinations".
An early version of the spec indicated that clients should process issuance
sequentially, following Link rel=next from an account URL to an authz URL, to a
new-cert URL. However, the spec has long since moved to putting these URLs in
the directory.
Certbot nominally supports either; This change consolidates on always using the
directory, simplifying things and making the transition to the latest ACME spec
easier.
* Revert "Revert "Remove Link rel=next for authzs and new-certs." (#4277)"
This reverts commit 11ec1eb911.
* Save new_authzr_uri with account for older clients.
* Add test that new_authzr_uri exists in regr.
* Restore backwards compatibility for new_authzr_uri.
* Fix account_test.
* Add test for deprecated URI argument to request_challenges.
* Review feedback.
* Fix test
* Add omitempty to new_cert_uri.
Per @pfg at https://community.letsencrypt.org/t/-/21318/2:
> This is not really true anymore - account recovery via email was planned to be added at some point, but has been removed from the spec since.
