* Set default value of SMTPFrom to empty string
This parameter should contain proper e-mail address (to be provided by user during configuration).
* Update default values in example/config.yaml
Default values and related comments in example/config.yaml are aligned
with values defined in internal/config/defaults.go.
Small improvements to foramting of config.yaml file.
* Add default value for AdvancedThrottlingRetryAfter to internal/config/defaults.go
AdvancedThrottlingRetryAfter was introduced in 70739d3 (superseriousbusiness/gotosocial#1466).
* Update config.yaml snippets in documentation
Currently, GtS only supports using the built-in LE client directly for
TLS. However, admins may still want to use GtS directly (so without a
reverse proxy) but with certificates provided through some other
mechanism. They may have some centralised way of provisioning these
things themselves, or simply prefer to use LE but with a different
challenge like DNS-01 which is not supported by autocert.
This adds support for loading a public/private keypair from disk instead
of using LE and reconfigures the server to use a TLS listener if we
succeed in doing so.
Additionally, being able to load TLS keypair from disk opens up the path
to using a custom CA for testing purposes avoinding the need for a
constellation of containers and something like Pebble or Step CA to
provide LE APIs.
