[Add Gitlab features to BuildStream 04/04/01]: Templates proposal

[Agustín Benito Bethencourt <agustin benito codethink co uk>]

Hi,

please review the proposal for the three templates. They are formatted in 
markdown:
1. Issue templates
1.1 Default template
1.2 Bug template
2. Merge request template
2.1  bst merge request

1. Issue templates

1.1 Default template

This is the template that will be seen as default when creating a new issue:

## Background

[//]: # (Provide a background or the root/source that justifies this task or 
action.)

## Task description

[//]: # (Short summary of the action to be executed)

* [ ] Action 1
* [ ] Action 2
* [ ] Action 3

## Acceptance Criteria

[//]: # (Acceptance criteria should follow the S.M.A.R.T. principle https://
en.wikipedia.org/wiki/SMART_criteria )

1.2 Bug template

This is the template for creating bugs:

## Summary

[//]: # (Summarize the bug encountered concisely)


## Steps to reproduce

[//]: # (How one can reproduce the issue - this is very important)


## What is the current bug behavior?

[//]: # (What actually happens)


## What is the expected correct behavior?

[//]: # (What you should see instead)


## Relevant logs and/or screenshots

[//]: # (Paste any relevant logs - please use code blocks ``` to format 
console output, logs, and code as it's hard to read otherwise. You can also 
add a Snippet and link it here.)

## Possible fixes

[//]: # (If you can, link to the line of code that might be responsible for 
the problem)

## Other relevant information

[//] # (Add the BuildStream version. Substitute below the "x" by "1" or "2". )

* BuildStream version affected: /milestone %BuildStream_v1.x

----
/label ~bug

------

2 Merge request template

This is the template for creating a merge request:

2.1 bst merge request

## Description

[//] # (Provide a description of the MR including what it resolves)

Changes proposed in this merge request:
* Change 1
* Change 2
* Change 3

This merge request,  when approved, will close issue #(issue #)

## CHANGELOG/Release Notes 

[//] # (Optional)

----

[//]: # <- These are comments that will only be shown when editing. No need to 
erase them.
/label ~bug <- label bug will be assigned by default to the ticket.
/milestone %BuildStream_v1.x where x is 1 or 2 defines the milestone 
(BuildStream version). When added at issue creation time, the milestone will 
be assigned automatically to the bug. 

What do you think?

Best Regards

-- 
Agustín Benito Bethencourt
Principal Consultant
Codethink Ltd