Rewrite lock_test.py (#9614)

`lock_test.py` is a weird, heavily customized, standalone testing relic that's giving me trouble because the name currently conflicts with `certbot/tests/lock_test.py`. Moving `certbot/tests` inside the Certbot package as discussed at https://github.com/certbot/certbot/issues/7909#issuecomment-1448675456 would avoid this, however, this is at least somewhat blocked on getting that test code passing lint and mypy checks again because we run those checks on the entirety of the Certbot package 🙃 Since `lock_test.py` could probably stand to be rewritten/refactored anyway, I took this approach.

What I did is I rewrote something largely equivalent to `lock_test.py` inside Certbot's unit tests. I chose not to do this in `certbot-ci` because its not necessary to have an ACME server available. We're no longer explicitly testing things with the nginx plugin here like we were in `lock_test.py`, however, we are checking that `prepare` is called on the plugin at the right time and I added comments about the importance of checking that we lock the directory during the call to `prepare` in the Apache and nginx test code.

As a bonus, this fixes https://github.com/certbot/certbot/issues/8121.

tox.ini

@@ -20,7 +20,7 @@ install_and_test = python {toxinidir}/tools/install_and_test.py
 dns_packages = certbot-dns-cloudflare certbot-dns-digitalocean certbot-dns-dnsimple certbot-dns-dnsmadeeasy certbot-dns-gehirn certbot-dns-google certbot-dns-linode certbot-dns-luadns certbot-dns-nsone certbot-dns-ovh certbot-dns-rfc2136 certbot-dns-route53 certbot-dns-sakuracloud
 win_all_packages = acme[test] certbot[test] {[base]dns_packages} certbot-nginx
 all_packages = {[base]win_all_packages} certbot-apache
-source_paths = acme/acme certbot/certbot certbot-apache/certbot_apache certbot-ci/certbot_integration_tests certbot-ci/snap_integration_tests certbot-ci/windows_installer_integration_tests certbot-compatibility-test/certbot_compatibility_test certbot-dns-cloudflare/certbot_dns_cloudflare certbot-dns-digitalocean/certbot_dns_digitalocean certbot-dns-dnsimple/certbot_dns_dnsimple certbot-dns-dnsmadeeasy/certbot_dns_dnsmadeeasy certbot-dns-gehirn/certbot_dns_gehirn certbot-dns-google/certbot_dns_google certbot-dns-linode/certbot_dns_linode certbot-dns-luadns/certbot_dns_luadns certbot-dns-nsone/certbot_dns_nsone certbot-dns-ovh/certbot_dns_ovh certbot-dns-rfc2136/certbot_dns_rfc2136 certbot-dns-route53/certbot_dns_route53 certbot-dns-sakuracloud/certbot_dns_sakuracloud certbot-nginx/certbot_nginx tests/lock_test.py
+source_paths = acme/acme certbot/certbot certbot-apache/certbot_apache certbot-ci/certbot_integration_tests certbot-ci/snap_integration_tests certbot-ci/windows_installer_integration_tests certbot-compatibility-test/certbot_compatibility_test certbot-dns-cloudflare/certbot_dns_cloudflare certbot-dns-digitalocean/certbot_dns_digitalocean certbot-dns-dnsimple/certbot_dns_dnsimple certbot-dns-dnsmadeeasy/certbot_dns_dnsmadeeasy certbot-dns-gehirn/certbot_dns_gehirn certbot-dns-google/certbot_dns_google certbot-dns-linode/certbot_dns_linode certbot-dns-luadns/certbot_dns_luadns certbot-dns-nsone/certbot_dns_nsone certbot-dns-ovh/certbot_dns_ovh certbot-dns-rfc2136/certbot_dns_rfc2136 certbot-dns-route53/certbot_dns_route53 certbot-dns-sakuracloud/certbot_dns_sakuracloud certbot-nginx/certbot_nginx
 
 [testenv]
 passenv =
@@ -32,7 +32,6 @@ commands_pre = python {toxinidir}/tools/pipstrap.py
 commands =
     win: {[base]install_and_test} {[base]win_all_packages}
     !win: {[base]install_and_test} {[base]all_packages}
-    python tests/lock_test.py
 # We always recreate the virtual environment to avoid problems like
 # https://github.com/certbot/certbot/issues/7745.
 recreate = true
@@ -104,7 +103,6 @@ basepython =
 commands =
     {[base]pip_install} acme[test] certbot[test] certbot-nginx
     pytest certbot-nginx
-    python tests/lock_test.py
 setenv =
     {[testenv:oldest]setenv}