Library naming

[daurnimator]

http://25thandclement.com/~william/projects/luaossl.html says "Lua OpenSSL" (in title)
The require string prefix is "openssl"
The repository name is "luaossl".

We need to be more consistent. I recommend using "luaossl" exclusively. This prevents any confusion with https://github.com/zhaozg/lua-openssl (which also uses the "openssl" require prefix; among others)

[daurnimator]

With openssl 1.1.1, openssl are (additionally) claiming the name "OSSL".
Best course of action seems to be that we adopt that too? (as a require prefix)