Issue #10473 - Better warnings in jetty.sh on filesystem permission issues

[joakime]

Adding more checks in jetty.sh for common file system permission issues.

Examples:

Don't have write/create access to JETTY_RUN directory path

[jetty-base]$ export JETTY_RUN=/var/run/jetty-no-exist
[jetty-base]$ ../jetty-home-10.0.17-SNAPSHOT/bin/jetty.sh start
mkdir: cannot create directory ‘/var/run/jetty-no-exist’: Permission denied
** ERROR: Unable to create directory: /var/run/jetty-no-exist
          Correct issues preventing use of $JETTY_RUN and try again.

Don't have write/create access to JETTY_PID file path location

Note: the /var/run/ path exist in the following tests, but the Jetty user doesn't have permissions to write there.

[jetty-base]$ export JETTY_PID=/var/run/jetty.pid
[jetty-base]$ ../jetty-home-10.0.17-SNAPSHOT/bin/jetty.sh start
Starting Jetty: touch: cannot touch ‘/var/run/jetty.pid’: Permission denied
** ERROR: Unable to touch file: /var/run/jetty.pid
          Correct issues preventing use of $JETTY_PID and try again.

Don't have write/create access to JETTY_STATE file path location

[jetty-base]$ export JETTY_STATE=/var/run/jetty.state
[jetty-base]$ ../jetty-home-10.0.17-SNAPSHOT/bin/jetty.sh start
Starting Jetty: touch: cannot touch ‘/var/run/jetty.state’: Permission denied
** ERROR: Unable to touch file: /var/run/jetty.state
          Correct issues preventing use of $JETTY_STATE and try again.