Provide a new command, gof3r info, which fetches metadata about an object.

[reem]

The new command will print some small bits of metadata about an object on success and will exit with a non-zero exit code on failure. The info command can be used to query for a file's existence without downloading it, and performs only a HEAD request.

[reem]

Will close #71 when merged.

[rlmcpherson]

Thanks, I'll take a look at this soon.

[reem]

I'm not a go expert, so please let me know if I did anything unidiomatic so I can correct it.

[BogdanSorlea]

@reem - I've created a similar thing starting from your branch, only my approach is different in that it does not require GetObject permission to obtain the info about the object, requiring only ListBucket permissions (convenient for security-tight scenarios where listing the bucket is allowed - and possibly putting objects in it, but not obtaining the objects from the bucket).

Anyways, this was the PR which I opened against this repo, although I meant to open it against our own master: https://github.com/rlmcpherson/s3gof3r/pull/118

It still requires tests and stuff, so it wasn't meant for immediate merge-in (but rather early review only), that's why it might look weird

I see the upstream repo is not really maintained anymore, so I have no huge hopes of it getting merged, but meh, I'm just throwing this out there