Add better STX icon about ledger-stacks

[neithanmo]

Hi @mark you can send us a 14x14 1-bit gif image, using our communication channel. so we can update the icon.

[markmhx]

@jleni can you help specify here what exact image format and dimensions, etc. are needed? We'll then provide the asset.

[jleni]

@markmhx any updates on this?

[eugeniadigon]

Hi all,
Here's the 1-bit gif version of the logo

[neithanmo]

thanks @eugeniadigon i will check if it works for us and then update it