Refact file interface

[wenxuwan]

What this PR does:

Add interface for file, and fix some known issues.#98, #301, #300

Which issue(s) this PR fixes:

Fixes #

Special notes for your reviewer:

Docment and Copy interface will be add later.

Does this PR introduce a user-facing change?:

[codecov]

Codecov Report

Merging #313 (28f51d6) into main (8c0d0f9) will increase coverage by 0.24%.
The diff coverage is 59.18%.

@@            Coverage Diff             @@
##             main     #313      +/-   ##
==========================================
+ Coverage   56.65%   56.90%   +0.24%     
==========================================
  Files          48       48              
  Lines        2058     2100      +42     
==========================================
+ Hits         1166     1195      +29     
- Misses        769      774       +5     
- Partials      123      131       +8     

Impacted Files	Coverage Δ
pkg/runtime/runtime.go	51.94% <0.00%> (ø)
pkg/grpc/api.go	72.16% <60.41%> (-0.23%)	⬇️

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[seeflood]

This a big pr that changes the File api definition. @zach030 @bokket Could you help review this PR?
After merging this PR ,we can then go ahead working on #299 #276