out_dynatrace: add configuration for Dynatrace based on http plugin

[hans-lougas-dt]

This commit introduces a new page for Dynatrace output based on http plugin.
It provides sample configuration and recommended steps and additional resources to enable Fluent Bit output for Dynatrace http endpoint.

[cnorris-cs]

I left comments and suggestions, but I've added my Technical Writing-based approval based on those to keep this moving.

[edsiper]

before merging this:

• @hans-lougas-dt

  • please sign off the commits (DCO error)
  • please use only 1 commit so we can keep the history clean

• @cnorris-cs

  • this page wont show up since the SUMMARY.md has not been modified. Looking at the Gitbook CI you can check the page is not there. (need live preview check before approvals)

• @agup006 is this ok, wanted to check if this is following your latest suggestion

[agup006]

LGTM!

[hans-lougas-dt]

Had to reset my master after squashing everything there and then I created a new pull request.
Please give it a look, it has all your co-authored changes as well: #1464