Add AltiumDesigner.gitignore

AltiumDesigner.gitignore

+# For PCBs designed using Altium Designer
+# Website: https://www.altium.com/altium-designer/
+
+# Directories containing cache data
+History
+__Previews
+
+# Directories containing logs and generated outputs
+Project\ Logs*
+Project\ Outputs*
+
+# Misc files generated by altium
+debug.log
+Status\ Report.txt
+*PcbDoc..htm
+
+# Lock files sometimes left behind
+.~lock.*