chore: remove evidence namespace

[rootulp]

Closes #1081

[github-actions]

PR Preview Action 6a9506a
🚀 Deployed preview to https://celestiaorg.github.io/celestia-app/pr-preview/pr-1619/
on branch gh-pages at 2023-04-14 07:57 UTC

[rootulp]

idk why some CI tasks was cancelled

[cmwaters]

Is it likely that the evidence namespace will come back?

[codecov-commenter]

Codecov Report

Merging #1619 (de6bff3) into main (dd19531) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             main    #1619   +/-   ##
=======================================
  Coverage   49.17%   49.17%           
=======================================
  Files          84       84           
  Lines        4948     4948           
=======================================
  Hits         2433     2433           
  Misses       2277     2277           
  Partials      238      238           

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[rootulp]

Is it likely that the evidence namespace will come back?

My impression is that evidence was originally moved from the Block struct to the data square to enable light clients to sample it rather than download it entirely. From in-person conversations during the Paris on-site, it seems like Evidence is small so we assume that light clients will be able to download it entirely. I think it's unlikely we move it back from the Block to the data square unless we observe that it is too large for light clients to download.