Replace documentation framework with Astro

[dlabaj]

Describe the enhancement

Currently the Pattern Fly team has to maintain it's own home grown framework to generate the patternfly documentation website. While this has serviced use well maintaining this comes with the caveat that the team needs to dedicated resources to update the framework. In 2022 Astro was introduced which is a highly extensible content delivery framework that uses the MD and MDX format. Looking at the current structure of our website, and how Astro works this would be a viable alternative to maintaining our own framework. I recommend doing a PoC / Spike to show the feasibility of this and determine if we would like to go ahead and migrate over to this framework.

Proposal: https://docs.google.com/document/d/1JXQGX2Ssis8WHI1pEaUeMbQ1nCUaZITIdapkOUmqBOQ/edit

CC: @nicolethoen @evwilkin @wise-king-sullyman @kmcfaul