feat: render request

[kriogenia]

Creates a renderer to use the placeholders and resolved values to render a new request with the replacements performed.

- feat: add iter to placecholders

• feat: render url
• feat: render headers
• chore: add errors
• feat: render query params
• feat: render formdata
• feat: render form urlencoded
• feat: render body raw and binary
• doc: placeholder and renderer
• feat: connect renderer