Port silecs cli to Python

Issue: #70 (closed)

silecs_cli/tests/examples/SilecsTestClassDU_invalid.silecsdeploy

+<?xml version="1.0" encoding="UTF-8"?>
+<SILECS-Deploy
+	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	silecs-version="2.3.0" created="08/16/2022" updated="08/16/2022"
+	xsi:noNamespaceSchemaLocation="/common/usr/cscofe/silecs/2.3.0/silecs-model/xml/DeploySchema.xsd">
+	<Information>
+		<Owner user-login="mnabywan" />
+		<Editor user-login="mnabywan" />
+	</Information>
+	<Deploy-Unit name="SilecsTestClassDU" version="0.1.0"></Deploy-Unit>
+	<SilecsDesign silecs-design-name="SilecsTestClass"
+		silecs-design-version="0.1.0" />
+	<Controller host-name="tsts7001">
+		<Siemens-PLC system="TIA-PORTAL" model="SIMATIC_S7-1500"
+			protocol="DEVICE_MODE" base-DB-number="1">
+			<Device silecs-device-label="dev0"
+				silecs-design-ref="SilecsTestClass" fesa-device-name="mySilecsTest"
+				fesa-fec-name="asl751"></Device>
+		</Siemens-PLCerror>
+	</Controller>
+</SILECS-Deploy>
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