Mantis 0001063: Add module for listing installable plugins.

git-svn-id: svn://svn.code.sf.net/p/openmediavault/code@1354 3c3d7b80-5828-415e-9f61-280b98178fff
Use update-ca-certificates instead of c_rehash.

git-svn-id: svn://svn.code.sf.net/p/openmediavault/code@1355 3c3d7b80-5828-415e-9f61-280b98178fff
Change email subject when sending a system diagnostic report.

git-svn-id: svn://svn.code.sf.net/p/openmediavault/code@1356 3c3d7b80-5828-415e-9f61-280b98178fff