fix: link and tweak issue template title

[raulb]

Description

• Makes title consistent compared with other templates.

• Fix link on the Readme.md.
• Include item for each builtin connector so it's pretty specific.

Quick checks

• I have followed the Code Guidelines.
• There is no other pull request for the same update/change.
• I have written unit tests.
• I have made sure that the PR is of reasonable size and can be easily reviewed.

[raulb]

Going to update the template to include the builtin connectors so those also have its own checkboxes.

[lovromazgon]

LGTM