[INFRA] Consider sharing all Issues and PR templates in the .github repository

[tbouffard]

Current situation

We have templates in this repository and also in the .github repository (to share the configuration for all repositories of the organization except this repository).
The content is duplicated and not accurate.

We have new needs to better guide people willing to contribute. For example, see

• [DOC] Update the Contributing Guide to specify where we want contribution in priority #2810
• [INFRA] Tag the issues for which contributions are desired on GitHub #2811
• [INFRA] Rework the Pull Request template #2872
• [INFRA] Rework the Issues templates #2882

Needs

Can we have a single set of templates for all repositories to reduce the maintenance?

Review if we can share more templates and if using specific templates is required in this repository.

Tasks

Beta Give feedback

1. Decide if we can only used shared templates --> No, the templates in the bpmn-visualization repository are too specific
2. If so, remove the templates from this repository and update the templates of the .github repository No, keep templates in the bpmn-visualization repository
3. If not, apply the recent improvements done in the bpmn-visualization repository to the .github repository --> feat: update the GitHub templates .github#33
4. Remove templates from https://github.com/process-analytics/mxgraph-sketch (duplicated from the .github repository) --> chore: remove GitHub templates mxgraph-sketch#89

[tbouffard]

All tasks are completed so closing this issue.