Fixes str vs byte mismatch, and some other minor changes

[tandasat]

This PR includes changes for followings:

• Fix or byte vs str mismatches causing exception like below and some other breaks

[+] SMRAM is at 0x88400000:887fffff
Traceback (most recent call last):
  File "smram_parse_orig.py", line 637, in <module>
    sys.exit(main())
  File "smram_parse_orig.py", line 614, in main
    d.dump_smst()
  File "smram_parse_orig.py", line 264, in dump_smst
    ptr = self.data.find('SMST\0\0\0\0')
TypeError: argument should be integer or bytes-like object, not 'str'

• Fix of the os.system error on Windows like this

'UEFIDump" "fw_image_1609190562' is not recognized as an internal or external command,
operable program or batch file.
WARNING: Error while running UEFIDump

• Update of the default customizable variables to the latest link and more generic paths
• Removal of training spaces