[feat.] Add cache module

   Moving the cache module from containerd/overlaybd to Photon

Signed-off-by: Yifan Yuan <[email protected]>

make it compiles with C++17/20/23

add set body buffer for http client

Signed-off-by: liulanzheng <[email protected]>

Fix getpagesize() when first used

Merge remote-tracking branch 'origin/release/0.7'

cherry-pick fix for timer stack overflow (#489)

support customized UserAgent in http client (#479)

Signed-off-by: liulanzheng <[email protected]>

http client support uds (#461)

add judgement for conflicted ONE_SHOT flag in add_interests() (#422)

improve logic in add_interests() and rm_interests()

When rm_interest needs to re-arm other interests, add EPOLLONESHOT