Added support for avrTiny 1 series attiny[24]1[246]

[innermatrix]

The differences between tinyAVR 1-Series 21x/41x (which are added in this PR) and tinyAVR 0-series 21x/41x (which are already supported by this crate) are documented in https://ww1.microchip.com/downloads/en/AppNotes/Microchip%20AN2636%20Migration%20Between%20tinyAVR%201-Series%20and%20tinyAVR%200-Series%2000002636A.pdf. Summary:

• DAC: none in 0-Series; 1 in 1-Series
• TCD: none in 0-Series; 1 in in 1-Series
• AC: Low-Power mode only in 0-Series; Fast mode or Low-Power mode in 1-Series
• EVSYS: 1/2 sync/async channeles in 0-Series; 2/4 sync/async channels in 1-Series
• TWI: default pin assignment only in 0-Series; default or alternate pin assignment in 1-Series
• CLKCTRL: 0-series can't drive an external oscillator; 1-series can

As a result, all of the 0-Series patch file applies to the 1-Series. The additional features in the 1-Series are handled as follows:

• DAC: no patch needed
• TCD: no patch needed
• AC: no patch needed
• EVSYS system: no patch needed
• TWI: no patch needed
• CLKCTRL: no patch needed

Overall, the 0-Series patch file applies to the 1-Series, and no additional patches are needed at this time to support the 1-Series

[Rahix]

Looks great, thanks a lot!