Add new options to delete-bucket command about b2_command_line_tool

[ppolewicz]

This duplicates in the large portion with the cli counterpart of Backblaze/b2-sdk-python#361 (already merged but not yet released due to a couple more PRs landing on the sdk side next week).

The basic idea would be to run b2 rm bucket-name '*' && b2 delete-bucket bucket-name and make it the responsibility of the user to make sure they are not uploading any more stuff to the bucket while they are trying to remove it completely.
Putting both in the same command could make sense, especially if we added --attempts 10 to try it many times in case some uploads keep landing - that'd be hard to achieve in a different way (without a special command to support it).

As for internals, it's a bit more complicated than in your design - the wildcard removal system uses a thread pool in order to increase performance - removing a file version is an io-bound call and putting those in python threads can make things much faster (here I believe it's nearly 10 times faster with default settings). Furthermore the streaming and backpressure are important considerations - a b2 bucket can contain a bazzilion objects and just their version ids might not fit within memory of the system that is trying to clean it. Anyway - that's merged now. I suggest that you wait for the cli counterpart of the mentioned PR to land and then chain that functionality in an optional mode of "delete-bucket", add a couple of tests and have a good feature.

I'm sorry about the review queue buildup, I've been horribly sick and could not review long PRs while two people were coding. I hope that clears up a lot in the next few days.

[metadaddy]

@ppolewicz Reopened and added new options.

[metadaddy]

@ppolewicz Please assign this one to me. I'll write some code and submit a PR. Thanks!

[metadaddy]

I suggest that you wait for the cli counterpart of the mentioned PR to land and then chain that functionality in an optional mode of "delete-bucket", add a couple of tests and have a good feature.

Sounds good to me!

I've been horribly sick and could not review long PRs while two people were coding. I hope that clears up a lot in the next few days.

Take it easy, and get well soon!

[metadaddy]

Closing now that 3.7.0 is available with rm command.