raspi with gpio.servo not work (like expected)

[gen2thomas]

I create this new issue to collect all various former issues related to gpio.ServoDriver().
The ServoWriter interface is used. For raspi, it should normally work also without pi-blaster for PWM0, PWM1. But this seems to be not implemented, because always the /dev/pi-blaster will be returned from the pwmPin() function.

So it seems this parts should be solved (something like a roadmap):

• introduce variadic function for gpio drivers, see roadmap(GPIO): use variadic constructor functions to allow for additional params, similar to i2c drivers #998
• introduce usage of normal PWM pin, without pi-blaster (with variadic functions)
• endpoints/angle not work like expected (adjustable with variadic functions), see Raspi servo does not work as expected #692
• fix pi-blaster usage (or the description how it needs to be configured), see Can't move servo using raspberry pi adapter and servo driver #703 , Servo doesn't work on raspberry pi #753

I'm going to close all the old referenced issues in favor of this one.

[gen2thomas]

fix released with v2.3.0