Tracking issue for no-std compliance for dependencies in ibc-rs and tendermint-rs

[soareschen]

This issue is part of #1158 to track the no-std support in dependencies that are used by ibc-rs and tendermint-rs. To fully support ibc-rs to be used in no-std environment like Substrate, we must also fix the dependencies by either fixing it upstream, or remove the dependencies from ibc-rs and tendermint-rs and replace them with alternatives that support no_std.

The checks are done by running no-std-check with only the specific unsupported dependency activated. Currently the checks are done from the branch at #1358.

• ics23 - Upstream fix yet to be merged in https://github.com/informalsystems/ics23/tree/soares/no-std.
• safe-regex - Upstream fix yet to be merged in https://github.com/informalsystems/safe-regex.
• crossbeam-channel - Requires std and is currently used by tendermint-light-client.
  • Removed
• tonic
  • Fails in all checks. We will have to remove the dependency to tonic from ibc-proto and tendermint-proto
  • Removed in Add --build-tonic flag to proto-compiler, sync protobuf script, and generate protobuf for std and no_std mode #1439
• socket2
  • Fails in all checks. It uses std and does not support Wasm targets.
• getrandom
  • Fails in check-wasm and check-substrate.
• ics23
  • Fix is merged in support ics23 no-std cosmos/ics23#41 but the changes are still unreleased.
• thiserror
  • Fails in all checks. We should have already removed all use of thiserror with flex-error, but still needs to double check.
  • Removed in Full support of no_std in ibc crate #1390.
• regex
  • Fails in check-wasm and check-substrate.
  • Use safe-regex as replacement in Use safe-regex instead of regex for regular expression #1395
• sled
  • Fails in all checks. We may have to remove dependency to sled.
• tokio
  • Fails in all checks.
• toml
  • Fails in all checks.
  • Dependency removed in Move out tendermint::config to tendermint-config crate tendermint-rs#986
• url
  • Fails in all checks.
  • Pending PR: no_std support for all crates servo/rust-url#717
  • Dependency removed in Move out tendermint::config to tendermint-config crate tendermint-rs#986

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[soareschen]

Closing this with #1858 tracking the last remaining dependency fix for safe-regex.