Replace abandoned php-jira-rest-client package?

[johanib]

In order to fix #1364, we needed to make some patches in the php-jira-rest-client library:

lesstif/php-jira-rest-client#547
lesstif/php-jira-rest-client#548
lesstif/php-jira-rest-client#549

For time being I merged these changes into our own fork.
After these changes have been merged back to the main library, we can remove our fork again from the composer.json, composer.lock and delete the github repo.

[johanib]

Update: two months later, and still no response in the library, despite other users wanting a release.
This means the continuity of the spdashboard / jira connection is not guaranteed, and might cause issues preventing php updates or package conflicts.

We should consider how to make this stable:

• Using a different package?
• Directly call the API using the bare minimum calls we need?
• Maybe see if there is another way to create tickets (email, csv import, etc)?