Add the ability to set custom DPI for android skin

[simple-elf]

Add the ability to set custom DPI for android skin

Now we have set of default skins https://aerokube.com/selenoid/latest/#_android_skin_skin, and also can set custom screen size, but it will always have DPI 160

But actual mobile devices uses big DPI on big resolutions

To achieve that, we need to create a custom skin for the emulator on the go, with needed dpi

Example of that I found on StackOverflow -https://stackoverflow.com/questions/4791943/emulating-density-of-320-dpi-on-android-emulator

[Litemn]

Better add ability to customize config.ini with any params

[vania-pooh]

@Litemn yep, that's more universal.