Database password is now read from file

Although, password file is checked during config validation, sth may have changed the
file content in the short period of time between validation and DB client initialization,
hence exiting in case of an error

state/persistent.go

@@ -5,6 +5,8 @@ import (
     "runtime"
     "context"
     "time"
+    "os"
+    log "log/slog"
 
     "webservice/configuration"
 
@@ -21,11 +23,18 @@ type Persistent struct {
 
 
 func NewPersistentStore( c *configuration.Config ) *Persistent {
+    content, err := os.ReadFile( c.DatabasePassword )
+    if err != nil {
+        log.Error( fmt.Sprintf( "Database password not able to be read: %v", err ) )
+        os.Exit( 1 )
+    }
+    dbPassword := string( content )
+
     return &Persistent{
         client: db.NewClient( &db.Options{
             Addr: fmt.Sprintf( "%s:%d", c.DatabaseHost, c.DatabasePort ),
             Username: c.DatabaseUsername,
-            Password: c.DatabasePassword,
+            Password: dbPassword,
             DB: c.DatabaseName,
 
             DialTimeout: time.Second * 3,