Backlog v1 -> v2 migration

[georgievgeorgi]

• Separate functionalities in a separate functions. Decorators that add methods to Spectrum cause problems. Methods should be included directly in the Spectrum definition
  • pure functions

  def fn(x: list | array_like, y: list | array_like, **kwargs) -> list | array_like

  • interface functions using spectrum

  def fn(in_spe: Spectrum, **kwargs) -> Spectrum | array_like | Any

  • Spectrum methods

  def fn(self: Spectrum, **kwargs) -> Spectrum | array_like | Any

• Simplify names of find_peak and fit_peak functions
• Remove SpectralComponents (deprecated)
• for x and y arrays mostly spe.x and spe.y are used. These perform copies of the spe._xdata and spe._ydata (where the actual arrays are stored). spe.__copy__(x=self.x, y=self.y) make other instances of the same numpy.arrays which is against the initial idea for the cache
• Multiple unnecessary calculations are done in rc2const. Resampled neon missing peaks. Reduce convolution width.