Sidekick64 v0.48 + Network features - alpha1

First public alpha version of experimental Sidekick64 kernels with network support compiled from this fork of Sidekick64. Sidekick64 was created by @frntc. Documentation can be found in README_network.md: https://github.com/hpingel/Sidekick64/blob/net-rebase-on-v0.48/README_network.md

• As a prerequisite use the v.048 Sidekick64 release of @frntc to create a working SD card: https://github.com/frntc/Sidekick64/releases
• The net/wlan kernel image(s) need(s) to be placed in the root folder of the SD card. The file sidekick64.txt in the root folder needs to be edited with the name of the kernel image that should be booted.
• wlan.zip is only needed for the WLAN kernel. It needs to be extracted to folder wlan. Folder wlan needs to be placed in the root folder of the SD card. The file wpa_supplicant.conf needs to be edited to add SSID and passphrase of your personal WLAN.
• raspberry_firmware_updated.zip provides current versions of some firmware files. This is not mandatory to use but recommended. The files in this folder replace files in the root folder of the SD card. Create backups of the old versions to be able to revert to them.

Full Changelog: https://github.com/hpingel/Sidekick64/commits/sk64-v0.48+net-alpha1