logging: Use RedirectStdLog

[francislavoie]

Fixes #4688

Before:

$ caddy trust --address localhost:2021 --ca local
2022/04/27 02:21:33.454 WARN    installing root certificate (you might be prompted for password)        {"path": "localhost:2021/pki/ca/local"}
2022/04/26 22:21:33 Note: NSS support is not available on your platform
2022/04/26 22:21:33 define JAVA_HOME environment variable to use the Java trust
2022/04/26 22:21:34 certificate installed properly in windows trusts

After:

$ caddy trust --address localhost:2021 --ca local
2022/04/27 02:39:49.365 WARN    installing root certificate (you might be prompted for password)        {"path": "localhost:2021/pki/ca/local"}
2022/04/27 02:39:49.367 INFO    Note: NSS support is not available on your platform
2022/04/27 02:39:49.367 INFO    define JAVA_HOME environment variable to use the Java trust
2022/04/27 02:39:50.939 INFO    certificate installed properly in windows trusts

[mholt]

Looks good, let's try it! Thanks Francis.