We need to use the original names for commit/tag content to match their hash;
otherwise git-fsck/git-clone would error and make cooked repositories
unusable.

This allows restoring objects as-is, so they match checksums;
even when the parser was lossy.

Related to T3916

Related to D6967

This also drops spurious copyright headers to those files if present.

Related to T3812

A few points were wrong/outdated.

This commit also adds a higher-level overview in the module docstring.

self._seen contains also all the objects on the todo-stacks,
so it's incorrect to use it here.

This divides the total wall time by ~2.

It can be confusing to just have 'Processing...' in the UI for hours.
With this change, a new progress update should be sent every few minutes.

In the swh-web UI, it will show only 'Processing... %d objects processed'
in the main table, but 'Over %d remaining' will be shown when hovering
the progress bar.
This does not show 'Processing... %d/%d' or a percentage, because the
number of remaining objects is not always known.

It seems the broken reference was only about the missing `s` so drop the intermapping
configuration.

Part of the broken build [1]

[1] https://jenkins.softwareheritage.org/job/DDOC/job/dev/6791/console

Related to T3648

This uses `swh-docs/swh/docs/sphinx/conf.py:intersphinx_mapping` config to resolve the
link.

Part of the broken build [1]

[1] https://jenkins.softwareheritage.org/job/DDOC/job/dev/6791/console

Related to T3648

There are too many corrupt objects currently, it's unreasonable
to crash every time there is one in a repository.

We should revert this commit when T3552 is resolved, though.

No change in swh-web will only show the first line;
but this will include the detailed error in notification emails.

Useful in docker to use mailhog instead of actually sending emails

gi-fsck (rightly) does not accept them.

This saves 30KB in the final archive.

Needed for debian builds to pass.

The interfaces were a bit messy, as bundle types sometimes included the object
type ('directory' was also a bundle type) and sometimes did not.

Instead, the bundle types now do not include the object type at all, which
means users do no have to care about what cooker will cook their bundle,
they just need to provide a bundle type.

Instead, the information about the object type is now carried along the
object id, in a SWHID.

This allows simplifying interfaces and removing multiple convertions
(especially between hex and bytes).

This is unfortunately a pretty large commit, as it is easier to change
everything at once, than to try to make it incrementally and adding
temporary convertions at some moving borders.

It also invalidates the existing cache entirely, as it used bundle types
and object ids as keys, which are now changed.

Using this type narrowing trick:
https://mypy.readthedocs.io/en/latest/literal_types.html#exhaustive-checks

Instead of parsing self.bundle_type on the fly in multiple places.

'obj_type' was confusing, because it means 'the type of objects in the
vault backend', which is actually made of an object type (dir/rev/...)
AND the cooker name.

Plus, I want to reuse the name 'obj_type' in a future commit to reference
what is actually the object type, in the swh-model definition.

It allows me to tweak the code to experiment