Refactor initiative carousel to show more initiatives

[georgimld]

On the landing page, change the carousel that currently shows the initiatives to either:

• Cards are shown vertically on the landing page
• New initiatives pages that show all the initiatives.

Notes:

• Change structure to a 3 or 4-column lazy load section. (No horizontal slider)
• Add filter options, especially an instant search filter

[zararsiz]

UI / Figma file:

https://www.figma.com/design/N21dWppxv7VJCpdfUPgCfK/KfW-%E2%80%93%C2%A0DEV-Handoff-(All-Sprints)?node-id=4096-22559&m=dev

[georgimld]

Will be replaced by issue #56