EXT packer

[paulnoalhyt]

• I have reviewed the OFRAK contributor guide and attest that this pull request is in accordance with it.
• I have made or updated a changelog entry for the changes in this pull request.

One sentence summary of this PR (This should go in the CHANGELOG!)

Add EXT packer, analyzer and tests.

Link to Related Issue(s)

#529

Please describe the changes in your request.

• Add ExtAnalyzer that uses the dumpe2fs command to determine all the EXT attributes.
• Add ExtPacker that uses the mke2fs command and the analysis from the ExtAnalyzer to create an EXT2/3/4 filesystem without having to mount anything or use loop devices.
• Add tests using FilesystemPackUnpackVerifyPattern and a round trip test to make sure attributes are preserved
• Note that I had to modify the _validate_folder_equality method in pytest_ofrak/src/pytest_ofrak/patterns/pack_unpack_filesystem.py because linux will sometimes create a lost+found directory when extracting the filesystem. But it could also be present in the original filesystem. So I just removed that from the equality comparison.

Compared to #558 PR, this merge request is more compact and less complex (no need to write a debugfs script, etc).

Anyone you think should look at this, specifically?

No

[rbs-jacob]

Before I get a chance to review this, how does it compare to these other components that Albert worked on? Also, does it happen to address concerns I raised a long time ago, when the EXT unpacking components were introduced?

• WIP ExtAnalyzer and ExtPacker components #558
• EXT Filesystem Components #337 (comment)

Note that this would close #529.

[paulnoalhyt]

@rbs-jacob, mentioned some of this in the PR description but can elaborate a bit more.

• WIP ExtAnalyzer and ExtPacker components #558 was brought to my attention as I was almost done writing this implementation. I think this implementation is more compact: I use the mke2fs to create an extfs from an existing directory, intead of building complex debugfs scripts.
• regarding EXT Filesystem Components #337 (comment), this PR does not make use of any loop device and doesn't require mounting anything. Everything is done in userspace using mke2fs for filesystem creation and dumpe2fs for getting information from extfs files.

[whyitfor]

This seems suspect? I don't think we want our packer to introduce files like this. Are we sure this is needed?

[paulnoalhyt]

Although not an EXT requirement, it is a convention to have a lost+found directory at the root of the filesystem. The mke2fs creates that directory here, without any option to not create it: https://github.com/tytso/e2fsprogs/blob/43643a57fb2d3368fbacd181a8cd713102d52a1a/misc/mke2fs.c#L3619
As this is a special case for the EXT component, I moved it from pytest_ofrak/src/pytest_ofrak/patterns/pack_unpack_filesystem.py to ofrak_core/tests/components/test_extfs_component.py in bb7e728