fix: fix Arazzo json pointers and other minor issues

[adamaltman]

What/Why/How?

This fixes a variety of issues:

• Fix Arazzo syntax to use JSON Pointer for body according to ABNF (Museum API Arazzo Example Issues #37 ).
• Add x-serverUrl examples in Arazzo.
• Update contributing file to correct for this specific repo where there are no release pipelines or docs folder.
• Streamline the PR template because one section doesn't make very much sense in this repo.
• Improve the sentence case pattern to allow for acronyms and allowing to remove the lint ignore file.
• Fix the index.md docs for consistency and to use the preview command.
• Clarify ticketDate description in the OpenAPI description.
• Remove package-lock.json as it shouldn't typically be distributed in a template type of repo.

Reference

• Fixes Museum API Arazzo Example Issues #37

Testing

• tested in my local environment.

Screenshots (optional)

Security

• Security impact of change has been considered
• Code follows company security practices and guidelines

[DmitryAnansky]

Last time I added changes to this file I intentionally updated the openapi.yaml with mock-server

servers:
  - url: "https://redocly.com/_mock/docs/openapi/museum-api"

The main idea was that users don't need to set any mock-server on their own and Spot run will work out of the box.

[DmitryAnansky]

Looks good to me,
I only have some doubts about x-serverUrl example.

[adamaltman]

I want to show how x-serverUrl is used in practice.