Allow replacement of banner artwork in Windows installer dialog

[scrmea]

The windows installer shows a distorted graphic, consisting of an overstretched icon.ico:

It would be much nicer if one could add a bmp of corresponding size to the src-tauri/icons folder.
The required dimensions are 493px × 58px.

A separate banner variable must link to the corresponding file here:

tauri/tooling/bundler/src/bundle/windows/templates/main.wxs

Line 35 in 3e6f341

<WixVariable Id="WixUIBannerBmp" Value="{{{icon_path}}}" />

[nothingismagick]

@lucasfernog - are we tracking this for the next release?

[lucasfernog]

@lucasfernog - are we tracking this for the next release?

Yeah I'll do it this morning.