DOC: re-phrase web README.md ENG
Basic rephrasing of the web README.md for improved legibility 
- "to navigate it " -> "to allow navigation of the website " ("it" is ambiguous here, "website" leaves no question as to which entity the instructions refer to.
- "it is needed" -> "must"
- "a not open" -> "it is not possible to open " (perhaps a typo here initially, sentence lengthened for improved legibility)




Thanks @anonmouse1 