Limit characters in environment variables

Current Situation

• The JS7 allows names of environment variables in uppercase spelling only.
• Names of environment variables are checked by the GUI, they are not checked by the API.

Desired Behavior

• The following characters are allowed for names of environment variables: a-z, A-Z, 0-9 and underscore
  • Spaces, hyphens, dots are not allowed.
  • Names have to start with a character, not with a digit.
  • No Unicode characters are allowed.
• The check for allowed characters in names of environment variables is performed by both the GUI and the API
• The GUI should not automatically convert user input of environment variables names to uppercase. It's the user's decision to use lowercase/uppercase spelling. However, Unix environments are case-sensitive for names of environment variables.