Technical release solving display issues with new CS7000-M17 and CS7000-M17 Plus hardware.

• Fixed bug in MD-UV3x0 audio volume management
• Fixed broken 1750Hz tone in MD-3x0
• Improved computation of battery state of charge
• Added 1750Hz tone to CS7000-M17 and CS7000-M17 Plus
• Added Dockerfile, devcontainer and vscode tasks for all targets

Thanks to:

• Marco DM4RCO
• Morgan ON4MOD
• Peter OE5BPA