Add no_std support to kairos-tx

[koxu1996]

This PR adds support for no_std in kairos-tx 🚀.

Note: I replaced thiserror with plain enum implementing fmt::Display, as advised by @Avi-D-coder 👏.

Closes #60.

[Avi-D-coder]

It would be nice to have a github action to build this with --no-default-features

[koxu1996]

@Avi-D-coder, do you want to build it with no_std and store the artifact, or you just want to see if it builds correctly?

[Avi-D-coder]

Just see if it builds correctly.

[github-actions]

File	Coverage
All files	61%	✅
kairos-server/tests/transactions.rs	83%	✅
kairos-test-utils/src/cctl/parsers.rs	66%	✅
kairos-crypto/src/implementations/casper.rs	3%	❌
kairos-server/src/routes/deposit.rs	86%	✅
kairos-server/src/routes/transfer.rs	73%	✅
kairos-server/src/routes/withdraw.rs	91%	✅
kairos-test-utils/src/cctl.rs	87%	✅
kairos-tx/src/asn.rs	77%	✅
kairos-tx/src/error.rs	0%	❌
kairos-server/src/config.rs	0%	❌
kairos-server/src/errors.rs	16%	❌
kairos-server/src/utils.rs	22%	❌

Minimum allowed coverage is 60%

Generated by 🐒 cobertura-action against fe85305

[koxu1996]

@Avi-D-coder I added extra CI check - it passed successfully:

I guess we need something similar for kairos-trie.

[Avi-D-coder]

Yeah added it now

[Avi-D-coder]

ignore the hercules failures they are unrelated.

[Avi-D-coder]

LGTM