Main page (change style & text)

[tursky]

1. I propose to center the content of the main page (for beauty). It will also improve the design of the Russian version. At the moment, the long RU-subtitle is partially wrapped on a new line (it breaks), and the main title does not fit at all (it is necessary to reduce the font size).
2. Remove "Copyright" before the author's name (because not necessary).
3. Replace "HowProgrammingWorks" with "Metarhia" (because clearer and appercases in Russian look so-so).

For example, "Metarhia contributors", or better - "Metarhia community"