Update documentation

After all the changes in the SR Sample Plugin epic have been done, the docs will need to get updated.

Sections affected:

• Setting up a Dev Environment
• Creating a Script Plugin
• Perhaps others/new ones will need added...

Things to fix include (but not limited to):

• Various places in the SR for Bitbucket and Confluence docs refer to Jira, when they should refer to the proper host application
• List of all the items which can be exported/imported using a .yaml file
• Script roots added by the samples
• Add note of https://ecosystem.atlassian.net/browse/ATLASSDK-145
• Lastly (but not least) probably the whole thing needs a couple of careful read overs...