Azure Blob Storage support

[dlangenk]

@mzur It works using the azurite emulator and the URLs provided by Rob Skelly (I'll forward you the mail). Could you please have a look, especially at the tests since I don't have any idea how the whole thing in PHP works.

[mzur]

Please use azure-oss/storage-blob-laravel instead of adding a custom implementation of the filesystem adapter here. This has to be added as a requirement to composer.json. The current state is missing league/flysystem-azure-blob-storage that is used here but this package is abandoned in favor of the azure-oss stuff.

[mzur]

I still see the StorageAdapter and FilesystemAdapter in there. This is no longer required if you use azure-oss/storage-blob-laravel, as everything is provided by the package. Also the requirements are still not defined in composer.json.

[mzur]

I sent a PR to the adapter repo and also asked for a new release that exposes the temporary URL support.

[mzur]

If users can't provide account credentials to generate SASes for temporary URLs on the fly, the adapter could fall back to the static SAS that the user has to update periodically by hand. Here is a possible implementation in AzureStorageBlobAdapter as diff:

9a10
> use League\Flysystem\UnableToGenerateTemporaryUrl;
25c26
<         $adapter = new AzureBlobStorageAdapter($containerClient, $config['prefix'] ?? $config['root'] ?? '');
---
>         $adapter = new AzureBlobStorageAdapter($containerClient, $config['prefix'] ?? $config['root'] ?? '', useDirectPublicUrl: true);
38a40,44
>     public function providesTemporaryUrls()
>     {
>         return true;
>     }
> 
49,53c55,63
<         return $this->adapter->temporaryUrl(
<             $path,
<             $expiration,
<             new Config(array_merge(['permissions' => 'r'], $options))
<         );
---
>         try {
>             return $this->adapter->temporaryUrl(
>                 $path,
>                 $expiration,
>                 new Config(array_merge(['permissions' => 'r'], $options))
>             );
>         } catch (UnableToGenerateTemporaryUrl $e) {
>             return $this->url($path);
>         }