Vendor libtrust

Signed-off-by: Derek McGowan <derek@mcgstyle.net> (github: dmcgowan)
Add libtrust key identity management

Signed-off-by: Derek McGowan <derek@mcgstyle.net> (github: dmcgowan)
Merge pull request #8112 from dmcgowan/libtrust_key_management

Libtrust key management