Include readme and installation instructions into release

### Prerequisites

- [x] This improvement has not already been suggested.
- [x] This improvement would be generally useful, not specific to my code or setup.
- [x] This improvement is not related to analysis quality (e.g. new rules, improvements to existing rules), which should be raised on the [SonarDelphi repository](https://github.com/integrated-application-development/sonar-delphi/issues).

### Engine area

Other

### Improvement description

Add readme and installation instructions.

### Rationale

Currently the package contains just 4 files, it's hard to tell what's the app, its source, author, how to install it, etc..

The issue mentions a package containing four files but names none; inspect those files and the repository's release layout first. Document what the app is, its source and author, and how to install it in a README, then verify the README and installation instructions are included in the release package.

Written by the indexing model from the issue text.