replacement for fastled sqrt16() (#4426)

* added bitwise operation based sqrt16

- replacement for fastled, it is about 10% slower for numbers smaller 128 but faster for larger numbers. speed difference is irrelevant to WLED but it saves some flash.

* updated to 32bit, improved for typical WLED use

- making it 32bits allows for larger numbers
- added another initial condition check for medium sized numbers
- increased the "small number" optimization to larger numbers: the function is currently only used to calculate sqrt(x^2+y^2) which even for small segments is larger than the initially used 64, so optimizing for 1024 makes more sense, although the value is arbitrarily chosen

wled00/fcn_declare.h

@@ -552,6 +552,7 @@ float asin_t(float x);
 template <typename T> T atan_t(T x);
 float floor_t(float x);
 float fmod_t(float num, float denom);
+uint32_t sqrt32_bw(uint32_t x);
 #define sin_t sin_approx
 #define cos_t cos_approx
 #define tan_t tan_approx