chore(docs): update QGB to "Blobstream"

[jcstein]

Overview

Part of #512

This PR renames instances of "QGB" to "Blobstream"

• rename non-programmatic instances of "QGB" c20ba56
• rename programmatic instances of qgb to new name

Checklist

• New and updated code has appropriate documentation
• New and updated code has new and/or updated testing
• Required CI checks are passing
• Visual proof for any user facing features like CLI or documentation updates
• Linked issues closed with keywords

[codecov-commenter]

Codecov Report

Merging #514 (fd505d9) into main (3c45307) will increase coverage by 0.10%.
Report is 8 commits behind head on main.
The diff coverage is n/a.

@@            Coverage Diff             @@
##             main     #514      +/-   ##
==========================================
+ Coverage   24.24%   24.35%   +0.10%     
==========================================
  Files          29       29              
  Lines        2949     2936      -13     
==========================================
  Hits          715      715              
+ Misses       2147     2134      -13     
  Partials       87       87              

see 1 file with indirect coverage changes