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GH-38699: [C++][FS][Azure] Implement `CreateDir()` (#38708)

### Rationale for this change

It seems that we can't create a directory explicitly without hierarchical namespace support.

It seems that Azure Blob Storage supports only virtual directory. There is no directory. If a file (blob) name has "/", it's treated that the file (blob) exists under a virtual directory.

It seems that Azure Data Lake Storage Gen2 supports a real directory.

See also:
https://learn.microsoft.com/en-us/azure/storage/blobs/storage-blobs-introduction

### What changes are included in this PR?

This change chooses the following behavior:

* Container can be created with/without hierarchical namespace support.
* Directory can be created with hierarchical namespace support.
* Directory can't be created without hierarchical namespace support. So do nothing without hierachical namespace support. (`arrow::Status::OK()` is just returned.)

### Are these changes tested?

Azurite doesn't support hierarchical namespace yet. So I can't test the implementation for hierarchical namespace yet. Sorry.

### Are there any user-facing changes?

Yes.
* Closes: #38699

Lead-authored-by: Sutou Kouhei <kou@clear-code.com>
Co-authored-by: Sutou Kouhei <kou@cozmixng.org>
Co-authored-by: Thomas Newton <thomas.w.newton@gmail.com>
Signed-off-by: Sutou Kouhei <kou@clear-code.com>