feat: add cache task api for grpc server

[gaius-qi]

Description

Related Issue

Motivation and Context

Screenshots (if appropriate)

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 297 lines in your changes missing coverage. Please review.

Project coverage is 15.75%. Comparing base (7b32688) to head (ff7d5dc).

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #548      +/-   ##
==========================================
- Coverage   15.84%   15.75%   -0.09%     
==========================================
  Files          53       53              
  Lines        7414     7456      +42     
==========================================
  Hits         1175     1175              
- Misses       6239     6281      +42     

Files	Coverage Δ
dragonfly-client-config/src/dfcache.rs	0.00% <ø> (ø)
...gonfly-client-init/src/container_runtime/docker.rs	0.00% <ø> (ø)
dragonfly-client/src/bin/dfcache/main.rs	0.00% <ø> (ø)
dragonfly-client/src/grpc/scheduler.rs	0.00% <0.00%> (ø)
dragonfly-client/src/gc/mod.rs	0.00% <0.00%> (ø)
dragonfly-client/src/announcer/mod.rs	0.00% <0.00%> (ø)
dragonfly-client/src/task/mod.rs	0.00% <0.00%> (ø)
dragonfly-client/src/grpc/dfdaemon_download.rs	0.00% <0.00%> (ø)
dragonfly-client/src/grpc/dfdaemon_upload.rs	0.00% <0.00%> (ø)