add uri schema for celo, zil

[danlipert]

Description

This PR adds testnet URI schema for Celo and the expected schema for ZIL

Refers/Fixes

n/a

Testing

untested

[codecov]

Codecov Report

Merging #6511 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #6511   +/-   ##
=======================================
  Coverage   27.07%   27.07%           
=======================================
  Files         291      291           
  Lines       26682    26682           
  Branches     3948     3948           
=======================================
  Hits         7223     7223           
+ Misses      19192    19188    -4     
- Partials      267      271    +4     

Impacted Files	Coverage Δ
app/dashboard/views.py	11.24% <0.00%> (ø)
...rketing/management/commands/no_applicants_email.py	0.00% <0.00%> (ø)
...eting/management/commands/assemble_leaderboards.py	40.48% <0.00%> (ø)

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[danlipert]

Tested this with the current build of the mobile app - it only supports raw address scanning right now, will update when I know the compatible build is coming out.