Allow sample names based on regular expresion

[luissian]

Description of feature

Sample id requirements in the sample sheet are:

The Sample_ID becomes a part of output file names. Sample IDs are not case-sensitive. Enter a sample ID with the following characteristics:

• Unique for the run.
• ≤ 40 alphanumeric characters, underscores, and/or dashes. Spaces and special characters are not allowed.
• If you use an underscore or dash, enter an alphanumeric character before and after the underscore or dash. Example: Sample1-T5B1_022515.

I would create a regex that fulfills this requirments removing the posibility of underscore, only