Replace cargo registry server's GIT index with sparse index

[pgarg66]

Problem

Sparse index is more suitable for the cargo registry server.

Summary of Changes

This PR replaces the temporary GIT index with a minimal sparse index.

Client's cargo configuration

Sparse index requires the client to configure it's registry as following

my-registry-sparse = { index = "sparse+http://<registry-server-ip>:<port>/index/" }

[codecov]

Codecov Report

Merging #33666 (5db3ba9) into master (d286c00) will increase coverage by 0.0%.
Report is 4 commits behind head on master.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master   #33666   +/-   ##
=======================================
  Coverage    81.8%    81.8%           
=======================================
  Files         806      806           
  Lines      217593   217593           
=======================================
+ Hits       178091   178110   +19     
+ Misses      39502    39483   -19     

[Lichtso]

The git2 dependency can be removed, right?

[pgarg66]

The git2 dependency can be removed, right?

Yes, that can be removed. I can do that in the next PR.