arrow

GH-40026: [C++][FS][Azure] Add support for reading user defined metadata (#40671)

### Rationale for this change

Users may want to set user defined metadata and/or properties such as `Content-Type`.

### What changes are included in this PR?

* Write user defined metadata.
* But the following metadata are written as properties:
  * `Content-Type`
  * `Content-Encoding`
  * `Content-Language`
  * `Content-Disposition`
  * `Cache-Control`
* The following metadata is ignored because corresponding properties are auto generated:
  * `Content-Hash`

### Are these changes tested?

Yes.

### Are there any user-facing changes?

Yes.
* GitHub Issue: #40026

Authored-by: Sutou Kouhei <kou@clear-code.com>
Signed-off-by: Sutou Kouhei <kou@clear-code.com>