Change base image to kasmvnc

[ilkersigirci]

Recently, linuxserver webtop move to kasm base image for better performance. Related blog post is here.

I think we can also profit from performance improvements if the base image will be changed.

[ilkersigirci]

I have tried to implement it myself in the dockerfile and it is working perfectly. Seamless clipboard and scrolling thanks to kasmvnc (chromium based browsers preferred for this, firefox support isn't perfect right now)

NOTE: /squashfs-root/obsidian --no-sandbox --disable-dev-shm-usage --disable-gpu --disable-software-rasterizer should be changed with /usr/bin/obsidian

[crosbyh]

I agree this would be an incredible change to see merged in. The kasm base image is so much faster!

[sytone]

Done, thanks for the contrib!