Add setShellPath method to customize shell path in Host class

[smartfire-tech]

• Bug fix #…?
• New feature?
• BC breaks?
• Tests added?
• Docs added?

Description

This PR adds a setShellPath method to the Host class, allowing users to define a custom shell path more easily when using Deployer.

Why this change is necessary

When using MySecureShell or other shell environments that do not support the -l option, Deployer's SSH command fails. By providing a dedicated method for setting the shell path, users can work around this issue without needing to manually override the shell path in the configuration.

What this PR does

• Adds setShellPath and getShellPath methods to the Host class.
• Allows users to set a custom shell path via the deploy.php configuration file.

Example

host('production')
    ->setHostname('your-hostname')
    ->setRemoteUser('your-user')
    ->setIdentityFile('~/.ssh/your-key')
    ->setShellPath('/bin/bash');  // Sets the shell path to /bin/bash