refactor: Error type

[hal3e]

closes: #1236

All the suggestions from the issue were incorporated. In addition, error messages were changed to follow the guidelines from rust-api-guidelines i.e. The error message given by the Display representation of an error type should be lowercase without trailing punctuation, and typically concise.

BREAKING CHANGE: the fuels-rs Error type is changed together with the error messages.

Checklist

• I have linked to any relevant issues.
• I have updated the documentation.
• I have added necessary labels.
• I have done my best to ensure that my PR adheres to the Fuel Labs Code Review Standards.
• I have requested a review from the relevant team or maintainers.

[segfault-magnet]

Great work.

I'd like to raise just one issue while we're on the subject of errors. Sometimes I feel like we should add more context to our errors.

Due to the use of ? in the sdk we just bubble up what are essentially low-level errors.

Failure to decode a contract response will be reported something like:
"Expected 8 B got 0" (off the top of my head)

"Not enough coins to fit the target"
without explaining that we were trying, for example, to cover gas costs or cover the users asset requirements.

Context can be added either by having every "layer" have its own errors or by having something akin to anyhow's Context where we can add more context in the form of Strings.

Ultimately resulting in:

Failed to call `get_large_state(). Cause: Other, Not enough coins to fit the target
Context:
0. calling `get_large_state`
1. preparing transaction
2. adding coins to fit gas costs

Striking a balance between the verbosity of a backtrace and the terseness of 'Not enough coins to fit the target'.

Since most of the context entries would not be something users would like to match on, maybe an option similar to anyhow's Context would be best?

Would mean wrapping the sdk Error in a struct and exposing the cause with a getter:

let call_result = contract_instance.methods()...;
if let Error(err) = call_result {
  let cause: Cause = err.cause();
  // match on cause if needed
  // Otherwise just print and get the cause and some context
  eprintln!("{}", err);
} 

[iqdecay]

Overall looks great, I have some questions (that maybe can be boiled down to personal preferences).

[iqdecay]

IMO Codec error should be used more often instead of Other, other than that some nitpicks.

[iqdecay]

LGTM!