CTC-2289 add resolver section to RT docs

[pokornyd]

• Brief description: adds new section to resolve rich text documentation for JS and TS and related code examples
• GitHub or Jira issue URL: https://kontent-ai.atlassian.net/jira/software/c/projects/CTC/boards/323?selectedIssue=CTC-2289
• When do you need the code to go public? Ideally ASAP.
• Is the pull request complete and ready for review? Yes

[pokornyd]

looking at this again and thinking... I wanted to have an extensive example, showcasing all the possibilities, but I guess it can be trimmed down slightly to not be so huge. let me know what you think.

[davidk2-kentico]

1/ I wonder if the case inconsistences have technical reason. E.g., const MyComponent vs. const parsedTree.
2/ I think it'd be beneficial to name the link mark (or whatever's the terminology for this) in a more descriptive way, e.g. externalLink as opposed to internalLink you have there.
But those are minor things. In your code I trust. xD

[pokornyd]

hey, thx for the review. let me follow up on your remarks :)

1. this is actually in line with naming conventions, as MyComponent is a React component, whose name should be PascalCased, whereas parsedTree is a regular TS variable (or a constant to be precise)
2. link is a default block type for external URLs in the PortableText standard, so I decided to keep it that way. internalLink is a custom block, representing a link to a content item, so it's Kontent.ai specific :)