Format tree audit details in Markdown

[matejchalk]

User story

• see Trees in audit details #990

Design

.                                            72%
└── src/                                     72%
    ├── app/                                 88%
    │   ├── components/                      68%
    │   │   └── login/                       48%
    │   │       └── login.component.ts       48%
    │   ├── services/                        97%
    │   │   ├── api-client.service.ts        99%
    │   │   └── auth.service.ts              94%
    │   ├── app.component.ts                 92%
    │   ├── app.config.ts                   100%
    │   └── app.routes.ts                   100%
    └── main.ts                               0%

Acceptance criteria

• render trees in audit details when generating report.md
• format tree as an ASCII code block
• align node data (e.g. coverage percentage), adjust to maximum line length