Add GitHub issue templates for bug reports and feature requests

[KyleTryon]

This pull request introduces standardized GitHub issue templates for the Cliparr project, making it easier for users to report bugs, request features, and start discussions. It also disables blank issues to ensure all submissions use a relevant template.

New GitHub Issue Templates:

• Added a bug report template to guide users in providing detailed information for troubleshooting, including media source selection, version details, browser info, and reproduction steps. (.github/ISSUE_TEMPLATE/bug_report.yml)
• Added a feature request template to collect suggestions for improvements or new capabilities, with prompts for feature description, problem statement, and extra context. (.github/ISSUE_TEMPLATE/feature_request.yml)
• Added a discussion template for general feedback, questions, or topics not covered by other templates, including fields for discussion topic and optional version/context details. (.github/ISSUE_TEMPLATE/discuss.yml)

Repository Configuration:

• Disabled blank issues to ensure all new issues use one of the provided templates. (.github/ISSUE_TEMPLATE/config.yml)