Ns/versionable unsupported

[nsarlin-zama]

closes: please link all relevant issues

PR content/description

Adds a trait and a type to mark deprecation of older versions of a type that are no longer supported.

Namely, there is a trait Deprecable that is used on a user facing type to tell that older versions of this type can be deprecated. This trait mainly defines some str associated constants that will be used to provide a friendlier error message to the user. In the example below, a user that tries to deserialize a deprecated version, would get the following error:

Deprecated MyStruct found in serialized data, minimal supported version is my_app v2

(In the context of tfhe-rs, this could be something like Deprecated ServerKey found in serialized data, minimal supported version is tfhe-rs v0.8)

The type Deprecated<MyStruct> should be used in the dispatch enum and replaces the deprecated versions. As it replaces them, it allows to remove all the code associated to defining, loading and upgrading them.

Since the remaining valid versions will still keep their place in the dispatch enum, any data that has not been explicitly deprecated will still be compatible.

Example:

use tfhe_versionable::deprecation::{Deprecable, Deprecated};
use tfhe_versionable::{Versionize, VersionsDispatch};
#[derive(Versionize)]
#[versionize(MyStructVersions)]
struct MyStruct;

impl Deprecable for MyStruct {
    const TYPE_NAME: &'static str = "MyStruct";
    const MIN_SUPPORTED_APP_VERSION: &'static str = "my_app v2";
}

#[derive(VersionsDispatch)]
#[allow(unused)]
pub enum MyStructVersions {
    V0(Deprecated<MyStruct>),
    V1(Deprecated<MyStruct>),
    V2(MyStruct),
}

We could also define a macro in tfhe-rs for the Deprecable trait implementation. (Something like deprecable!(ServerKey))

Check-list:

• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)
• Relevant issues are marked as resolved/closed, related issues are linked in the description
• Check for breaking changes (including serialization changes) and add them to commit message following the conventional commit specification

[IceTDrinker]

Looks good small things I saw