* Remove overly specific PHP RNG instructions (that's just built into PHP7 through random_bytes now, which will throw if no suitable RNG is available)
* Remove PHP 5 RNG requirements, since we don't support that PHP release any mre
* Remove verbose explanation of PHP 5.6 support
* Remove conflicting instructions for PHP memory limits
* Remove version numbers from supporetd databases other than MySQL, it's up to the community modules to define that
* Remove Oracle support (code is nine years old!)
* Make "community supported" status clearer on databases, people can draw their own conclusions as open source users on Github
* Remove IIS version number, I think we should just stick to "needs web.config" and not give the impression that this is actively tested
* Remove mention of OSes for web servers, that's kind of irrelevant in today's hosting world (containers, PaaS, etc)
* Shorten install instructions in favour of a "quickstart" and point to lessons instead
* Remove mention of archive download option, we really shouldn't promote this - composer is the de-facto standard
* Add generic descriptions of the hosting environment considerations without going too much into specifics
* Remove Apache version number, we don't test on different versions, and really mostly rely on mod_rewrite working properly. Laravel does the same (doesn't claim specific Apache version support)
