restrict customer list on patch-panel-port/edit to current customers only

[nickhilliard]

[BF] restrict customer list on patch-panel-port/edit to current customers only

Currently the Member/Customer field on patch-panel-port/edit shows non-current members. This patch alters the datasource call to select only current members.

In addition to the above, I have:

• ensured all relevant template output is escaped to avoid XSS attached with <?= $t->ee( $data ) ?> or equivalent.
• ensured appropriate checks against user privilege / resources accessed
• API calls (particular for add/edit/delete/toggle) are not implemented with GET and use CSRF tokens to avoid CSRF attacks