Better installation documentation

[nijikokun]

Missing crucial details as follows:

• Distribution Packages docs.konghq.com#15
• Configuring Kong to find Cassandra (separate from configuration documentation)
• Notifications about having NGiNX while using Kong with OpenResty
• Better notice of third-party libraries (openssl for luasec for example)

Side details:

• Configuration fully documented (what each property is for)

[thibaultcha]

make install and that's all for source install. (if all the dependencies are there). install.md used to have per-platform install instructions but... Package managers will do most of the work anyways.
For OSX, same, we used to have an install.md but we don't anymore, we apparently rely on getkong.org/download now.

Also see Kong/docs.konghq.com#15, because they overlap

[nijikokun]

Also see Kong/docs.konghq.com#15, because they overlap

True, updated

[thibaultcha]

What's the status here? Can we close? Documentation doesn't seem to be a problem so far, we can wait for more input maybe.

[nijikokun]

Documentation is really good, haven't heard any complaints or issues about following it. Only praises, closing 👍.

Nice work everyone :)