Go binding: Finish implementation of the Maybe module

## Go binding: Finish implementation of the Maybe module

| Item | Detail |
|---------|-----------------------|
| Binding | `Go` |
| Module | `Morphir.SDK.Maybe` |
| Relevant Morphir.IR.SDK module| [`Morphir.IR.SDK.Maybe`](https://github.com/finos/morphir-elm/blob/main/src/Morphir/IR/SDK/Maybe.elm)
| Relevant `morphir-jvm` code |[`morphir.sdk.Maybe`](https://github.com/finos/morphir-jvm/blob/main/morphir/sdk/core/src/morphir/sdk/Maybe.scala) |
| Relevant Elm Module | [`Maybe`](https://github.com/elm/core/blob/master/src/Maybe.elm)|

Provide a Go lang implementation of the `Morphir.SDK.Maybe` module for `Morphir.SDK`.

The implementation should include all the functionality for Maybe as well as tests (we are willing to have this split across PRs).

Please place it here: https://github.com/finos/morphir/tree/features/polyglot-morphir/corelib/go/morphir/sdk/

Start in corelib/go/morphir/sdk/ and compare the referenced Morphir.IR.SDK.Maybe, morphir.sdk.Maybe Scala, and Elm Maybe modules to identify the required functionality. Add the Go implementation and its tests; done means the Maybe module covers the corresponding functionality and the tests pass.

Written by the indexing model from the issue text.