Vibrational spectrscopy module update and normal mode animation

[ppravatto]

This pull request introduces the following improvements:

• Implemented a more efficient algorithm for plotting infrared spectra using NumPy array vectorization, significantly speeding up spectrum computation.
• Adopted normalized lineshape functions for spectral broadening of integrated intensity values, replacing the previous unit-height functions which were less physically meaningfull.
• Refactored the spectrum plotting function to allow users to plot spectra on a pre-existing Matplotlib axis.
• Introduced normal mode animations based on VMD tools, along with automatic zoom adjustment to enhance visualization quality.
• Updated the documentation accordingly.
• Added an example page demonstrating practical applications of SPyCCI to real-world computational chemistry problems.

Open issue:
One aspect remains unresolved and requires clarification: the relationship between the molar extinction coefficient and the integrated intensity. A question has been posted on the ORCA forum, but no response has been received yet. I will update issue #46 to keep track of this.

[lbabetto]

A question has been posted on the ORCA forum, but no response has been received yet.

Can you link to the post? Curious to follow it as well

[ppravatto]

A question has been posted on the ORCA forum, but no response has been received yet.

Can you link to the post? Curious to follow it as well

My original post is this: https://orcaforum.kofo.mpg.de/viewtopic.php?f=8&t=14030&p=55859#p55859. Unfortunately, I have not received any reply to date.