Assets: support range requests for alt representations

[cjao]

• I have added the tests to cover my changes.
• I have updated the documentation and CHANGELOG accordingly.
• I have read the CONTRIBUTING document.

[cjao]

The changes here allow one to download a specific byte range of an asset's string representation. This may be useful for rendering large assets in the UI.

[codecov]

Codecov Report

Merging #1890 (37e9912) into develop (d94bdaf) will increase coverage by 0.50%.
Report is 1 commits behind head on develop.
The diff coverage is 100.00%.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #1890      +/-   ##
===========================================
+ Coverage    84.43%   84.93%   +0.50%     
===========================================
  Files          294      180     -114     
  Lines        14389    11180    -3209     
  Branches       195        0     -195     
===========================================
- Hits         12149     9496    -2653     
+ Misses        2106     1684     -422     
+ Partials       134        0     -134     

Flag	Coverage Δ		*Carryforward flag
Dispatcher	92.30% <100.00%> (-0.04%)	⬇️
Functional_Tests	?
SDK	79.27% <ø> (-0.04%)	⬇️	Carriedforward from d94bdaf
UI_Backend	?
UI_Frontend	?

*This pull request uses carry forward flags. Click here to find out more.