feat(meta): add essentials to default features

[yash-atreya]

Motivation

Currently, the meta crate doesn't enable full feature by default which contains features that give access to the provider and contract API.

Solution

Added a new essentials feature and enabled it by default.

essentials = ["contract", "provider-http", "rpc-types", "signer-local"]

Note: Users that don't require all of the above, should use default-features = false and selectively add features to features = [] in their Cargo.toml.

PR Checklist

• Added Tests
• Added Documentation
• Breaking changes