doc: add Gitlab issue templates

# Bug report

## Summary

> Brief summary of the bug encountered

## Steps to reproduce

> Describe precisely all steps needed to reproduce the bug

> What's the current behavior ?

> What is the expected correct behavior ?

## Library version

> Which version where you using?

> Add a list of your deps and versions (pip freeze or conda)

## Relevant screenshots/logs/whatever material useful

## Possible fixes

> If relevant, you can suggest fixes

/label ~"type:: bug" "status:: needs triage"

/assign @remihuguet 

# Documentation needed

## Summary

> Brief summary of the documentation you think should be improved or created

## Context

> Describe the context of the documentation

## Proposed structure

> Propose some plan for the documentation to be created

## Relevant screenshots/logs/whatever material useful

/label ~"type:: docs" "status:: needs triage"

/assign @remihuguet 

# New feature needed

## Summary

> Brief summary of the feature you wish

## Context

> Describe the context of the feature

## Examples usage

> Describe some scenario / examples usage

## Relevant screenshots/logs/whatever material useful

/label ~"type:: feature" "status:: needs triage"

/assign @remihuguet