Created tutorial for master Excel creation

docs/tutorials/1-creating-master-excel.md

docs/tutorials/data/DLCs_onshore/DLC12_IEC61400-1Ed3.txt

docs/tutorials/data/DLCs_onshore/DLC13_IEC61400-1Ed3.txt

docs/tutorials/data/DLCs_onshore/DLC14_IEC61400-1Ed3.txt

docs/tutorials/data/DLCs_onshore/DLC15_IEC61400-1Ed3.txt

docs/tutorials/data/DLCs_onshore/DLC21_IEC61400-1Ed3.txt

docs/tutorials/data/DLCs_onshore/DLC22b_IEC61400-1Ed3.txt

docs/tutorials/data/DLCs_onshore/DLC22y_IEC61400-1Ed3.txt

docs/tutorials/data/DLCs_onshore/DLC23_IEC61400-1Ed3.txt

docs/tutorials/data/DLCs_onshore/DLC24_IEC61400-1Ed3.txt

docs/tutorials/data/DLCs_onshore/DLC31_IEC61400-1Ed3.txt

docs/tutorials/data/DLCs_onshore/DLC32_IEC61400-1Ed3.txt

docs/tutorials/data/DLCs_onshore/DLC41_IEC61400-1Ed3.txt

docs/tutorials/data/DLCs_onshore/DLC42_IEC61400-1Ed3.txt

docs/tutorials/data/DLCs_onshore/DLC51_IEC61400-1Ed3.txt

docs/tutorials/data/DLCs_onshore/DLC61_IEC61400-1Ed3.txt

docs/tutorials/data/DLCs_onshore/DLC62_IEC61400-1Ed3.txt

docs/tutorials/data/DLCs_onshore/DLC63_IEC61400-1Ed3.txt

docs/tutorials/data/DLCs_onshore/DLC64_IEC61400-1Ed3.txt

docs/tutorials/data/DLCs_onshore/DLC81_IEC61400-1Ed3.txt