Add ability to disable Jira add-ons at start time

Problem Definition:

In some cases, JIRA would not be able to startup due to a specific plugin that is installed in the instance. Then, we would need to startup the instance by moving the plugins out of the installed-plugins folder manually before starting up JIRA to make sure that the instance at least is accessible.

This is the current steps to start JIRA in safe mode:

1. Stop JIRA
2. Navigate to JIRA Home folder > plugins
3. Rename the installed-plugins to anything else.
4. This will make JIRA create the folder again but, without any plugin inside.
5. Start JIRA.

Then, nothing will be initialized as the folder empty and JIRA starts in safe mode. But, this is not exactly simple to perform.

Suggested Solution

To have a specific flag that will make JIRA to startup in safe mode without making changes in that folder.

Note on fix

Starting from Jira 7.3 there are 2 new start-up options:

--disable-all-addons (or /disablealladdons for windows users)
--disable-addons=<addon keys> or (/disableaddons=<addon keys> for windows users)

• disable-all-addons does not disable all addons, but merely only those that are non-system (i.e marketplace addons, or custom addons), in some places this is referred to as "user-installed".
• disable-addons takes a colon-separated list (chosen as a colon is the only prohibited character from a plugin key) of addons to be disabled. These can be system addons.
  • be used to disable JIRA application OBR bundles, i.e

    ./bin/start-jira.sh --disable-addons=com.atlassian.jira.jira-software-application
    

• As of 7.3 these features does not work in Datacenter mode, the parameters are ignored if present when JIRA is configured to work in a cluster.