chore(config): upgrade to gosettings v0.4.0

- drop qdm12/govalid dependency
- upgrade qdm12/ss-server to v0.6.0
- do not unset sensitive config settings (makes no sense to me)

internal/configuration/settings/log.go

@@ -1,7 +1,10 @@
 package settings
 
 import (
+	"fmt"
+
 	"github.com/qdm12/gosettings"
+	"github.com/qdm12/gosettings/reader"
 	"github.com/qdm12/gotree"
 	"github.com/qdm12/log"
 )
@@ -9,35 +12,33 @@ import (
 // Log contains settings to configure the logger.
 type Log struct {
 	// Level is the log level of the logger.
-	// It cannot be nil in the internal state.
-	Level *log.Level
+	// It cannot be empty in the internal state.
+	Level string
 }
 
 func (l Log) validate() (err error) {
+	_, err = log.ParseLevel(l.Level)
+	if err != nil {
+		return fmt.Errorf("level: %w", err)
+	}
 	return nil
 }
 
 func (l *Log) copy() (copied Log) {
 	return Log{
-		Level: gosettings.CopyPointer(l.Level),
+		Level: l.Level,
 	}
 }
 
-// mergeWith merges the other settings into any
-// unset field of the receiver settings object.
-func (l *Log) mergeWith(other Log) {
-	l.Level = gosettings.MergeWithPointer(l.Level, other.Level)
-}
-
 // overrideWith overrides fields of the receiver
 // settings object with any field set in the other
 // settings.
 func (l *Log) overrideWith(other Log) {
-	l.Level = gosettings.OverrideWithPointer(l.Level, other.Level)
+	l.Level = gosettings.OverrideWithComparable(l.Level, other.Level)
 }
 
 func (l *Log) setDefaults() {
-	l.Level = gosettings.DefaultPointer(l.Level, log.LevelInfo)
+	l.Level = gosettings.DefaultComparable(l.Level, log.LevelInfo.String())
 }
 
 func (l Log) String() string {
@@ -46,6 +47,11 @@ func (l Log) String() string {
 
 func (l Log) toLinesNode() (node *gotree.Node) {
 	node = gotree.New("Log settings:")
-	node.Appendf("Log level: %s", l.Level.String())
+	node.Appendf("Log level: %s", l.Level)
 	return node
 }
+
+func (l *Log) read(r *reader.Reader) (err error) {
+	l.Level = r.String("LOG_LEVEL")
+	return nil
+}