Migrate to tempfile for libcontainer and youki crate

[yihuaf]

As explained in #1883, we would like to move away from rolling out our own tempdir implementation. This is the first PR to migrate libcontainer and youki crate. The libcgroup and integrate_test will follow.

A few notes:

First, I remove using test name to create unique tempdir. Since the tempdir are designed to go away once out of the scope, using random names is enough to create unique tempdir. The directory will be removed regardless of test successful or not, so there is no reason to use human readable names.

Second, a number of test is partly re-written so it works better with the tempdir crate. Notably, we introduced scopeguard and defer!() to recreate the Drop delete a specific path that is not inside a tempdir logic. I find this to communicate the intent of the test more clear.

Third, for Rootless, I decided to introduce dependency injection to make the uid/gid mapping path configurable, so test can pass in a path instead of hardcode to a specific path.

[codecov-commenter]

Codecov Report

Merging #1887 (a83a5fd) into main (5c31fae) will increase coverage by 0.03%.
The diff coverage is 91.63%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1887      +/-   ##
==========================================
+ Coverage   67.57%   67.61%   +0.03%     
==========================================
  Files         125      125              
  Lines       14199    14204       +5     
==========================================
+ Hits         9595     9604       +9     
+ Misses       4604     4600       -4     

[yihuaf]

@utam0k Addressed the review. PTAL :)

[utam0k]

Thanks

[utam0k]

😍