Disallow slashes in identifiers

[xeronimus]

As a solution for issue #287 slashes and backslashes should not be allowed in identifiers.

Acceptance Criteria

• The following identifiers should be sanitized:
  • branch name
  • build name
  • use case name
  • scenario name
  • page name
• The sanitizing should be done as follows
  • forward slashes should be replaces with underscore ( "/" --> "_")
  • backward slashes should be replaces with underscore ( "\" --> "_")

[adiherzog]

See also https://github.com/scenarioo/scenarioo/wiki/Safe-Identifiers

[adiherzog]

I removed the question mark again because it actually does not make problems. So it's only slashes and backslashes that are note allowed in identifiers.