fix(cheqd): make cosmos payer seed optional

[TimoGlastra]

Makes the cosmos payer seed optional, as you can also used it as a holder without payer seed.

[TimoGlastra]

@berendsliedrecht can you re-review. I also added an overwrite of the Buffer global. Not sure though if we should do this?

[berendsliedrecht]

@berendsliedrecht can you re-review. I also added an overwrite of the Buffer global. Not sure though if we should do this?

Ideally only for the cheqd specific dependencies. Since you would do this in your app anyways to make it work, I think it is okay.

[codecov-commenter]

Codecov Report

Merging #1547 (f86deaa) into main (8f2d593) will increase coverage by 1.39%.
The diff coverage is 60.00%.

@@            Coverage Diff             @@
##             main    #1547      +/-   ##
==========================================
+ Coverage   84.34%   85.73%   +1.39%     
==========================================
  Files         950      950              
  Lines       22743    22744       +1     
  Branches     3977     3978       +1     
==========================================
+ Hits        19183    19500     +317     
+ Misses       3337     3059     -278     
+ Partials      223      185      -38     

Files Changed	Coverage Δ
packages/cheqd/src/CheqdModuleConfig.ts	100.00% <ø> (ø)
packages/cheqd/src/ledger/CheqdLedgerService.ts	80.85% <33.33%> (ø)
packages/cheqd/src/CheqdModule.ts	100.00% <100.00%> (ø)

... and 15 files with indirect coverage changes