reorganize files (#5199)

* reorganize files

1. make it easier to find files
2. reduce scrolling to get to README on main view of repo

* remove tr.txt again

books/free-programming-books-ro.md

@@ -0,0 +1,38 @@
+### Index
+
+* [Ajax](#ajax)
+* [HTML](#html)
+* [MySQL](#mysql)
+* [PHP](#php)
+  * [Symfony](#symfony)
+* [Scratch](#scratch)
+
+
+### Ajax
+
+* [Ajax](http://etutoriale.ro/articles/1483/1/Tutorial-Ajax/)
+
+
+### HTML
+
+* [HTML](http://tutorialehtml.com/ro/introducere-in-html/)
+
+
+### MySQL
+
+* [MySQL](http://profs.info.uaic.ro/~busaco/teach/courses/net/docs/mysql-ro.pdf) (PDF)
+
+
+### PHP
+
+* [PHP](http://php.punctsivirgula.ro)
+
+
+#### Symfony
+
+* [Symfony 5: Curs rapid](https://symfony.com/doc/current/the-fast-track/ro/index.html)
+
+
+### Scratch
+
+* [Informatica Creativa](http://scratched.gse.harvard.edu/resources/informatica-creativa-0)