feat: Make rug-backend optional for mithril-client crate

[Mr-Leshiy]

Content

To allow disable LGPL usage which discussed in, added rug-backend feature for mithril-client and mithril-common crates.

Issue(s)

Closes #1786

[Mr-Leshiy]

About the CI failure.
I've run this hash_computation_is_quicker_with_a_full_cache test locally and it passes.
Also seems to me that what testing under this test is not actually related to my changes.
So to be honest dont know what to do with it.

[jpraynaud]

LGTM 👍

@Mr-Leshiy, thank you for the contribution!

Before we can merge your PR, could you?

• tidy up a bit the commit history as we don't squash commits when merging
• add an entry in the CHANGELOG.md file at the root of the repository for this new feature
• bump the patch versions of mithril-client, mithril-common and mithril-stm

[sfauvel]

LGTM

[Alenar]

LGTM.

I would have really liked to avoid using default-features = false for the mithril-common import in mithril-client, but as much as I can scratch my head there's no acceptable alternatives that come in mind.

[Mr-Leshiy]

@jpraynaud @sfauvel @Alenar

Thanks for your feedback !

I've made requested changes for CHANGLELOG.md file, bumping versions and squashing commits.

[jpraynaud]

@Mr-Leshiy actually your commits need to be signed in order to be merged in the main branch.
Can you re-push them with your signature?

[jpraynaud]

Hi @Mr-Leshiy, on top of signing the commits, could you also sync your fork and make sure that the crates versions in your PR have not already been used by another PR in the mean time?

[Mr-Leshiy]

@jpraynaud done 🚀

[jpraynaud]

@jpraynaud done 🚀

Thanks @Mr-Leshiy, I guess that all the commits need to be signed and I see that only the last one is signed now.
Maybe a force push can force the signature of the commit 62b8a90.

We'll be able to merge the PR as soon as this is the case 🚀