Make options follow suit for fyne package (or vice versa)

[chran554]

Is your feature request related to a problem? Please describe:

It would be nice if the command lines of fyne and fyne-cross commands looked and worked as the other as much as possible.

Describe the solution you'd like to see:

The amount of dashes before each option: use one "-" or two "--". (Is it a (help option) documentation issue?)
The format of the parameters: use camelCase or kebab-case

I've also noticed that the icon path differs between both commands.

In fyne it seem to be relative to the source.
fyne package --sourceDir cmd/fynehelloworld --name "HW App" --appID="com.dummy.id" --appVersion="1.2.3" --appBuild=42 --icon ../../star-icon.png

In fyne-cross" it seem to be relative the place where the command is issued (default value of diroption?).fyne-cross darwin -arch=arm64 -name "HW App" -app-id="com.dummy.id" -app-version="1.2.3" -app-build=42 -icon="star-icon.png" cmd/fynehelloworld`

[andydotxyz]

Fyne is going through a review of the parameters as we tidy up into a new "tools" repo. It is expected that fyne-cross work will follow that, once it is all set out.