[WFLY-4172] Enable the -secmgr parameter for tests if the security.manager property is defined.

I left these commits separate as they seemed to make more sense that way. I can squash them together or squash specific ones together if that seems to make more sense.

### Commit 4f60129
This is the main commit for the JIRA and simply enables the testsuite to enable the security manager by passing `-Dsecurity.manager` to the build.

Note that a dummy property is passed in the `<jboss.args/>` property defined in the parent test suite pom. If left blank system property is set to `null` which in when parsed by arquillian becomes `${jboss.args}` as that's the argument in the arquillian.xml file.

### Commit a326301
Enables the security manager extension by default for all server types.

### Commit 69579df
Fixes some issue found with generating the permissions.xml for deployments.

### Commit 56ee9a1
Fixes a few issues found when running the web integration tests under the security manager.