Improve and test jetty.sh behaviors

[joakime]

This is a branch of PR #10700

It adds Docker testing, which may or may not be a good idea (performance wise / time wise)

[joakime]

@gregw this is the new PR with jetty.sh changes, including testing various configurations on docker instances.

[gregw]

I think we still need the double quotes

Suggested change

	JETTY_ARGS[${#JETTY_ARGS[@]}]=$XMLFILE
	JETTY_ARGS[${#JETTY_ARGS[@]}]="$XMLFILE"

I did the following test:

[] TEST=("foo" "bar")

[] echo ${FOO[*]}
foo bar bob

[] TEST=("foo" "bar")

[] echo ${TEST[*]}
foo bar

[] TEST[2]=bob

[] echo ${TEST[*]}
foo bar bob

[] TEST[3]=with space
bash: `TEST[3]': not a valid identifier
Command 'space' not found, but can be installed with:
sudo snap install space

[] TEST[3]="with space"

[] echo ${TEST[*]}
foo bar bob with space

[gregw]

Oh!!!! It works because it is a single variable:

[] WITH_SPACES='var with spaces'

[] TEST[4]=$WITH_SPACES

This is sooooo subtle! bash is getting more perl like!