Update Sponsorship Prospectus on website and Enable button to download

[snehithallamraju]

https://in.pycon.org/2023#sponsors

Please find attached file
PyCon IN23 Sponsorship Prospectus Final.pdf

[inovizz]

Please don't use above PDF, I am working on to provide an updated one

[bhansa]

@inovizz shall we add a drive link once done?