feat(core): add presign support for obs

[cuichenli]

fixes: #2070

noticed that oss already have the presign support, so this pr only touches obs.

[cuichenli]

some side notes:

noticed there are a lot of code duplicates, for instance: obs_get_head_object_request and obs_get_head_object share the same logic on setup the req object, not sure if it would be worth to extract the shared logic?

also for the sign_query method, not sure if it would be worth to make it as a trait?

[Xuanwo]

not sure if it would be worth to extract the shared logic?

We can call xxx_request in xxx.

also for the sign_query method, not sure if it would be worth to make it as a trait?

Make it a trait is not helpful because one service one has one valid sign_query implementaion.

[cuichenli]

thanks, updated based on the comments above.

[suyanhanx]

Thanks. Let's go.