feat(rust): run postscripts in a chroot

[imobachgs]

Problem

https://trello.com/c/I8bWv2ZR

The current scripting support does not allow using AutoYaST chroot-like scripts. For instance, if you want to enable a system service at the end of the installation, you need to deal with the chroot yourself.

Solution

This change extends the post-scripts to run on a chroot on the target system. A definition like the following will enable the sshd daemon at the end of the installation:

scripts: {
  post: [
    { name: 'test', body: '#!/bin/bash\nsystemctl enable sshd', chroot: true },
  ],
}

Now, chroot-ed postscripts are the default. Since you most likely want to run postscripts on a chroot, we are supporting chroot: false for backward compatibility reasons.

Refactoring

The PR contains a heavy refactoring of the scripts model. Now, we are using an enum-based approach that makes it easier to cope with the potential differences between script types, given that not all are equal. We followed that approach in the network area and it worked quite well.

By now, the only difference is the chroot attribute. However, in the future, we expect that prescripts and postscripts will get support for additional features, like progress reporting, that will not be available for init scripts.

Testing

• Tested manually

[coveralls]

Pull Request Test Coverage Report for Build 12087532632

Details

• 41 of 94 (43.62%) changed or added relevant lines in 4 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-0.05%) to 70.981%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
rust/agama-lib/src/scripts/client.rs	0	1	0.0%
rust/agama-server/src/scripts/web.rs	0	2	0.0%
rust/agama-lib/src/scripts/store.rs	0	11	0.0%
rust/agama-lib/src/scripts/model.rs	41	80	51.25%

Totals
Change from base Build 12082384586:	-0.05%
Covered Lines:	16953
Relevant Lines:	23884

---

💛 - Coveralls

[jreidinger]

Overall change looks good, but I expect to see somewhere documentation for it including example of usage.