Combine PAA5100 and PMW3901 into a single module for #301

[Gadgetoid]

There were two sets of bindings which mapped onto one single driver class. This change cleans up that unnecessary bloat and maintenance burden by merging them into a single "module" exposing two modules to MicroPython sharing mostly the same code.

They diverge only with "make_new" which uses a wrapped constructor to set a chip type which we can refer to later if any special handling is needed for one device or the other:

mp_obj_t BreakoutPMW3901_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *all_args) {
    return make_new(ChipType::PMW3901, type, n_args, n_kw, all_args);
}

mp_obj_t BreakoutPAA5100_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *all_args) {
    return make_new(ChipType::PAA5100, type, n_args, n_kw, all_args);
}

mp_obj_t make_new(enum ChipType chip, const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *all_args) {
    breakout_pmw3901_BreakoutPMW3901_obj_t *self = nullptr;
    ...

This is demonstrated in the print magic method. IE, even though they are the same module, the following:

import breakout_paa5100
import breakout_pmw3901

paa = breakout_paa5100.BreakoutPAA5100()
pwm = breakout_pmw3901.BreakoutPMW3901()

print(paa)
print(pwm)

Will output:

>>> %Run -c $EDITOR_CONTENT
BreakoutPAA5100(spi = 0, cs = 17, sck = 18, mosi = 19, miso = 16, int = 20)
BreakoutPMW3901(spi = 0, cs = 17, sck = 18, mosi = 19, miso = 16, int = 20)