implement basic plugin factory

mythril/laser/ethereum/plugins/plugin_factory.py

@@ -0,0 +1,18 @@
+from mythril.laser.ethereum.plugins.plugin import LaserPlugin
+from mythril.laser.ethereum.plugins.implementations.benchmark import BenchmarkPlugin
+from mythril.laser.ethereum.plugins.implementations.mutation_pruner import MutationPruner
+
+
+class PluginFactory:
+    """ The plugin factory constructs the plugins provided with laser """
+
+    @staticmethod
+    def build_benchmark_plugin(name: str) -> LaserPlugin:
+        """ Creates an instance of the benchmark plugin with the given name """
+        return BenchmarkPlugin(name)
+
+    @staticmethod
+    def build_mutation_pruner_plugin() -> LaserPlugin:
+        """ Creates an instance of the mutation pruner plugin"""
+        return MutationPruner()
+