Add DMT6008LFG N-Channel MOSFET

Datasheet: https://www.diodes.com/assets/Datasheets/DMT6008LFG.pdf

Matching footprints:

• https://gitlab.com/kicad/libraries/kicad-footprints/-/blob/master/Package_SON.pretty/Diodes_PowerDI3333-8.kicad_mod?ref_type=heads

#General Guidelines: All contributions to the kicad library must follow the KiCad library convention

Thanks for creating a pull request to contribute to the KiCad libraries! To speed up integration of your PR, please check the following items:

• Remove the instructional content of this template
• Provide a URL to a datasheet for the symbol(s) you are contributing
• An example screenshot image is very helpful
• Ensure that the associated footprints match the official footprint library
  • A new fitting footprint must be submitted if the library does not yet contain one.
• If there are matching footprint PRs, provide link(s) as appropriate
• Check the output of the automated check scripts - fix any errors as required
• Give a reason behind any intentional library convention rule violation.