Translate missing English steps

[niccokunzmann]

Website-link: https://github.com/CoderDojoPotsdam/regex-tutorial/tree/master/steps

Expected Behavior

I expect all German steps to be also available in English

Actual Behavior

Steps 11, 12 and 13 are missing

Actions to Reproduce

English https://coderdojopotsdam.github.io/regex-tutorial/steps/00-01-introduction.html is shorter than
German https://coderdojopotsdam.github.io/regex-tutorial/steps/00-01-einfuehrung.html

Solution Description

Translate the missing steps by copying the files and writing the text in English.

Hints

• adapt the readmefile https://github.com/CoderDojoPotsdam/regex-tutorial/tree/master/steps#readme
  to match what you do to add the steps