Update Issue Templates to follow other Powertools runtimes best practices

[machafer]

Update Issue Templates to follow other Powertools runtimes best practices(Python & .Net)

• Add maintenance template: https://github.com/awslabs/aws-lambda-powertools-python/blob/develop/.github/ISSUE_TEMPLATE/maintenance.yml
• Add Share your work template: https://github.com/awslabs/aws-lambda-powertools-python/blob/develop/.github/ISSUE_TEMPLATE/share_your_work.yml
• Add Documentation Improvements template: https://github.com/awslabs/aws-lambda-powertools-python/blob/develop/.github/ISSUE_TEMPLATE/documentation_improvements.yml
• Disable Blank issues and Add Ask a general question template; https://github.com/awslabs/aws-lambda-powertools-python/blob/develop/.github/ISSUE_TEMPLATE/config.yml
• Add missing "triage" label to Documentation template:

[jeromevdl]

closed with #1062