Cargo registry server updates to download crates

[pgarg66]

Problem

cargo fetch need fixes, as it currently doesn't return a crate package.

Summary of Changes

• Return the crate package as response to the download command
• Use base16 for program ID. Using base58 doesn't work as it is case sensitive, and fetch uses lower case for all the values
• Return just the crate file, and do not include meta data information.

Fixes #

[codecov]

Codecov Report

Merging #33805 (a741b33) into master (6fd0dcb) will decrease coverage by 0.1%.
Report is 1 commits behind head on master.
The diff coverage is n/a.

@@            Coverage Diff            @@
##           master   #33805     +/-   ##
=========================================
- Coverage    81.8%    81.8%   -0.1%     
=========================================
  Files         806      806             
  Lines      217428   217428             
=========================================
- Hits       178056   178040     -16     
- Misses      39372    39388     +16