Add data migrations for removing confidential investor logic.

[Neopallium]

The migrations for PR #1493

[codecov[bot]]

Codecov Report

Merging #1494 (94b2574) into develop (9ce5eab) will decrease coverage by 0.13%. The diff coverage is 15.38%.

@@             Coverage Diff             @@
##           develop    #1494      +/-   ##
===========================================
- Coverage    54.12%   53.99%   -0.13%     
===========================================
  Files          145      145              
  Lines        32401    32484      +83     
===========================================
+ Hits         17537    17541       +4     
- Misses       14864    14943      +79     

Files Changed	Coverage Δ
pallets/identity/src/lib.rs	22.05% <1.29%> (-3.42%)	:arrow_down:
pallets/asset/src/lib.rs	82.30% <92.85%> (+0.09%)	:arrow_up:

... and 3 files with indirect coverage changes