Increased robustness of dockerfile generator for Fedora distros.

[matejak]

• Changed literal ^fedora$ match to basically ^fedora.*
• Reimplemented enablement of additional repositories.

[pep8speaks]

Hello @matejak! Thanks for submitting the PR.

• In the file generate-dockerfile.py, following are the PEP8 issues :

Line 16:80: E501 line too long (118 > 79 characters) Line 17:80: E501 line too long (222 > 79 characters) Line 19:80: E501 line too long (229 > 79 characters) Line 21:80: E501 line too long (92 > 79 characters) Line 23:80: E501 line too long (179 > 79 characters) Line 49:80: E501 line too long (84 > 79 characters) Line 76:80: E501 line too long (88 > 79 characters) Line 92:80: E501 line too long (81 > 79 characters) Line 201:80: E501 line too long (81 > 79 characters) Line 219:80: E501 line too long (89 > 79 characters) Line 221:80: E501 line too long (94 > 79 characters) Line 292:80: E501 line too long (80 > 79 characters) Line 293:80: E501 line too long (80 > 79 characters) Line 362:80: E501 line too long (82 > 79 characters) Line 376:80: E501 line too long (80 > 79 characters) Line 401:80: E501 line too long (94 > 79 characters)