Update the science page, and publish the questionnaire results of year 2024 (#96)

Updates the science page, and publish the questionnaire results of year 2024

- 2024: I've put the entire results for public. But removed a link from it to the detailed responses which may contain personal info.
- 2020: I took away the figure from main page and added as an updated slide to the existing pdf file.
P.S. The failing of linkcheck is not related to this commit, an issue opened listing the failing links: #97

Author: khsrali

docs/pics/Questionnaire_results_2024.pdf

@@ -2,19 +2,15 @@
 
 ## AiiDA-powered research projects
 
-The AiiDA team conducts an **annual survey** on the [AiiDA mailing list](./mailing_list.md) to gather information on research projects using AiiDA, including papers published, [AiiDA plugins](https://aiidateam.github.io/aiida-registry/) used, and further database indicators that inform future development choices.
+The AiiDA team conducts periodically a **survey** in parallel with each development milestone, formerly on the [AiiDA mailing list](./mailing_list.md) and now on [Discourse](https://aiida.discourse.group/), to gather information on research projects using AiiDA, including papers published, [AiiDA plugins](https://aiidateam.github.io/aiida-registry/) used, and further database indicators that inform future development choices.
 
-- **2020**: [results](../pics/aiida-powered-research-projects-2020.pdf)
+- **2024**: [results](../pics/Questionnaire_results_2024.pdf)
+- **2020**: [results](../pics/aiida-powered-research-projects-2020_Updated.pdf)
 - **2019**: [results](http://bit.ly/2HRjTWo)
 
 ## AiiDA-powered publications
 
-:::{figure} ../pics/publication-chart.png
-A histogram of publications containing calculations powered by AiiDA, selected from the
-[citations of the AiiDA paper](https://scholar.google.com/scholar?cites=10268089832296963062&as_sdt=2005&sciodt=0,5&hl=en).
-:::
-
-If you use AiiDA in your research and your paper is not listed on this page, feel free to send us an [email](mailto:developers@aiida.net) with the DOI of your paper.
+If you use AiiDA in your research and your paper is not listed on this page, feel free to contact us via [Discourse](https://aiida.discourse.group/) with the DOI of your paper.
 
 
 ### Publications<sup>*</sup> from 2024 (up to March)