refactor(models): ubah inheritance model ke base class

- Mengubah inheritance pada semua model di `Modules/Lpj` dari `Model` ke `Base` untuk konsistensi struktur.
- Menghapus model `SLA` beserta migrasi terkait karena tidak lagi digunakan.

app/Models/PenawaranDetailTenderLog.php

@@ -7,7 +7,7 @@ use Illuminate\Database\Eloquent\Factories\HasFactory;
 use Illuminate\Database\Eloquent\Relations\BelongsTo;
 // use Modules\Lpj\Database\Factories\PenawaranDetailTenderFactory;
 
-class PenawaranDetailTenderLog extends Model
+class PenawaranDetailTenderLog extends Base
 {
     use HasFactory;
 
@@ -22,7 +22,7 @@ class PenawaranDetailTenderLog extends Model
     {
         return $this->belongsTo(PenawaranTender::class, 'penawaran_id', 'id');
     }
-    
+
     public function penawarandetail(): BelongsTo
     {
         return $this->belongsTo(PenawaranDetailTender::class, 'detail_penawaran_id', 'id');