feat: File Type Filtering

[michaelmsonne]

Feature Request

Describe the Feature Request

Enable filtering by file type (EXE, DLL, SYS, etc.) during selection.?

Describe Preferred Solution

Describe Alternatives

Related Code

Additional Context

If the feature request is approved, would you be willing to submit a PR?
Yes / No (Help can be provided if you need assistance submitting a PR)

[michaelmsonne]

For now, when adding files all supported for signtool.exe (Microsoft) is added... is this needed?