Move to yaml-based configuration

This commit updates the configuration to be yaml-based and updates the
configuration to read in a yaml file.

internal/config/domains.go

@@ -1,79 +0,0 @@
-package config
-
-import (
-	"fmt"
-	"strings"
-
-	"github.com/tkw1536/goprogram/lib/collection"
-)
-
-// This file contains domain related derived configuration values.
-
-// HTTPSEnabled returns if the distillery has HTTPS enabled, and false otherwise.
-func (cfg Config) HTTPSEnabled() bool {
-	return cfg.CertbotEmail != ""
-}
-
-// HostRequirement returns a traefik rule for the given names
-func (Config) HostRule(names ...string) string {
-	quoted := collection.MapSlice(names, func(name string) string {
-		return "`" + name + "`"
-	})
-	return fmt.Sprintf("Host(%s)", strings.Join(quoted, ","))
-}
-
-// HTTPSEnabledEnv returns "true" if https is enabled, and "false" otherwise.
-func (cfg Config) HTTPSEnabledEnv() string {
-	if cfg.HTTPSEnabled() {
-		return "true"
-	}
-	return "false"
-}
-
-// HostFromSlug returns the hostname belonging to a given slug.
-// When the slug is empty, returns the default (top-level) domain.
-func (cfg Config) HostFromSlug(slug string) string {
-	if slug == "" {
-		return cfg.DefaultDomain
-	}
-	return fmt.Sprintf("%s.%s", slug, cfg.DefaultDomain)
-}
-
-// DefaultHostRule returns the default traefik hostname rule for this distillery.
-// This consists of the [DefaultDomain] as well as [ExtraDomains].
-func (cfg Config) DefaultHostRule() string {
-	return cfg.HostRule(append([]string{cfg.DefaultDomain}, cfg.SelfExtraDomains...)...)
-}
-
-// SlugFromHost returns the slug belonging to the appropriate host.'
-//
-// When host is a top-level domain, returns "", true.
-// When no slug is found, returns "", false.
-func (cfg Config) SlugFromHost(host string) (slug string, ok bool) {
-	// extract an ':port' that happens to be in the host.
-	domain, _, _ := strings.Cut(host, ":")
-	domain = TrimSuffixFold(domain, ".wisski") // remove optional ".wisski" ending that is used inside docker
-
-	domainL := strings.ToLower(domain)
-
-	// check all the possible domain endings
-	for _, suffix := range append([]string{cfg.DefaultDomain}, cfg.SelfExtraDomains...) {
-		suffixL := strings.ToLower(suffix)
-		if domainL == suffixL {
-			return "", true
-		}
-		if strings.HasSuffix(domainL, "."+suffixL) {
-			return domain[:len(domain)-len(suffix)-1], true
-		}
-	}
-
-	// no domain found!
-	return "", ok
-}
-
-func TrimSuffixFold(s string, suffix string) string {
-	if len(s) >= len(suffix) && strings.EqualFold(s[len(s)-len(suffix):], suffix) {
-		return s[:len(s)-len(suffix)]
-	}
-	return s
-}