Added wiki details for crowdin best practices

close #208
Use markdown-style links instead of <a> tags in README.md
CB-6344 CB-6698 `after` for `<config-changes>`, `<framework>` for Android

close #210
CB-6698 Remove explicit `<source-file>` from example since `<framework>` now copies it in by default
Added details for people wishing to help translate
CB-2606 Base directory of <icon src= is the project directory NOT the www directory