[Dev] Add a way for people to add information to our saved crossbow data

We should have a simple + ligthweight way to annotate specific builds with information like "won't be fixed until dask has a new release" or "this is supposed to be fixed in ARROW-XXX".

We should find an easy, lightweight way to add this kind of information.

Only relevant in its previous parent: -We **should not** require, ask, or allow people to add this information to the JSON that is saved as part of ARROW-13509. That JSON should be kept pristine and not have manual edits. Instead, we should have a plain-text look up file that matches notes to specific builds (maybe to specific dates?)-

**Reporter**: [Jonathan Keane](https://issues.apache.org/jira/browse/ARROW-13062) / @jonkeane

_{**Note**: *This issue was originally created as [ARROW-13062](https://issues.apache.org/jira/browse/ARROW-13062). Please see the [migration documentation](https://github.com/apache/arrow/issues/14542) for further details.*}

Start by locating the saved Crossbow build data and the JSON associated with ARROW-13509. Define a separate plain-text lookup file for notes tied to specific builds or dates, while keeping the saved JSON pristine; done means users can add and retrieve annotations without manually editing that JSON.

Written by the indexing model from the issue text.