* commands: Add TLS/HTTPS support to hugo server
The "auto cert" handling in this PR is backed by mkcert (see link below).
To get this up and running on a new PC, you can:
```
hugo server trust
hugo server --tlsAuto
```
When `--tlsAuto` (or `--tlsCertFile` and `--tlsKeyFile`) is set and no `--baseURL` is provided as a flag, the server is
started with TLS and `https` as the protocol.
Note that you only need to run `hugo server trust` once per PC.
If you already have the key and the cert file (e.g. by using mkcert directly), you can do:
```
hugo server --tlsCertFile mycert.pem --tlsKeyFile mykey.pem
```
See https://github.com/FiloSottile/mkcertFixes#11064
Primary motivation is documentation, but it will also hopefully simplify the code.
Also,
* Lower case the default output format names; this is in line with the custom ones (map keys) and how
it's treated all the places. This avoids doing `stringds.EqualFold` everywhere.
Closes#10896Closes#10620
