* Adding git publish to toolkit

* grafana-toolkit new feature plugin:github-release

* Feedback from code review
1. Used async await and exec for executing commands
2. Using dist folder to get plugin information

* Reverting change to plugin.json back to original value.

* reverted changes to yarn.lock

* reverted changes to yarn.lock

* feedback from code review

* feedback from code review 2

* moved constants to recommended functions

* styling changes and reverting yarn.lock

* removing changes to package.json

* replced execLine with execa

* better error detection around the publish token

* made simpler with commitHash from build

* Testing showed a number of required changes:
- Make the sha configurable
  or through environment variable
  or through git config.
- Allow a release to be recreated
- Set name and repo from git config as this is what
ghr is expecting anyway.
- Appropriate errors if the user
  tries to run a release without
  doing a ci-build and ci-package first.

* Using spinner.
Took out extra dependencies out of project.json
wrote tests manually.

* Updated tests. Now passing

* Adding git publish to toolkit

* grafana-toolkit new feature plugin:github-release

* Feedback from code review
1. Used async await and exec for executing commands
2. Using dist folder to get plugin information

* Reverting change to plugin.json back to original value.

* reverted changes to yarn.lock

* reverted changes to yarn.lock

* feedback from code review

* feedback from code review 2

* moved constants to recommended functions

* styling changes and reverting yarn.lock

* removing changes to package.json

* replced execLine with execa

* better error detection around the publish token

* made simpler with commitHash from build

* Testing showed a number of required changes:
- Make the sha configurable
  or through environment variable
  or through git config.
- Allow a release to be recreated
- Set name and repo from git config as this is what
ghr is expecting anyway.
- Appropriate errors if the user
  tries to run a release without
  doing a ci-build and ci-package first.

* Using spinner.
Took out extra dependencies out of project.json
wrote tests manually.

* Updated tests. Now passing

* updated test for reducers, from master

* package.json and yarn.lock from master