Support for -tls-cert and -tls-key to point to a certificate and
key to encrypt communications between the user and hydroxide.
Support for -tls-client-ca to ask client to present a certificate
signed by the provided CA.
Closes: https://github.com/emersion/hydroxide/issues/13
Hi, I had a problem where the suggested usage is not actually how hydroxide was able to parse flags.
Currently, `hydroxide help` claims the correct order is
`usage: hydroxide <command> <flags>`
However, my flags are silently ignored when placing them in that order.
```
# hydroxide serve -smtp-port 2024
2020/07/01 01:43:20 CardDAV server listening on 127.0.0.1:8080
2020/07/01 01:43:20 SMTP server listening on 127.0.0.1:1025
2020/07/01 01:43:20 IMAP server listening on 127.0.0.1:1143
```
So I goofed with it a while and found out that hydroxide will not ignore flags if they go *before* the command.
```
hydroxide -smtp-port 2024 serve
2020/07/01 01:44:12 CardDAV server listening on 127.0.0.1:8080
2020/07/01 01:44:12 SMTP server listening on 127.0.0.1:2024
2020/07/01 01:44:12 IMAP server listening on 127.0.0.1:1143
```
The usage information should be changed to reflect this.
proletarius101
primalmotion
Simon Ser
Hubcapp