Add stand alone DMCA policy

[cindywu]

our DMCA policy is hidden in our terms and conditions https://poster.jellypbc.com/terms

i would like our DMCA policy to be on a stand alone page and front and center, so there is no ambiguity in how we treat copyrighted content.

an example: https://www.outline.com/dmca.html

our policy in plain english is: do not publicly share copyrighted content. if we find you publicly sharing copyrighted content, we will take it down.

[cindywu]

https://linear.app/issue/JEL-27/add-stand-alone-dmca-policy