chore: improve issue and PR templates

[nabdelgadir]

Description

Improve issue and pull request templates.

Related issues

• connect to Improve issue & pull-request templates (connectors, LB3) loopbackio/loopback-next#3886

Checklist

• New tests added or existing tests modified to cover all changes
• Code conforms with the style guide

[nabdelgadir]

See #102 for linter fixes

[dhmlau]

@nabdelgadir , i think we'd still want users to open bugs/features for connector specific issues in here instead of against the loopback-next repo. So maybe we can use PR https://github.com/strongloop/loopback-connector-mongodb/pull/551/files as a reference? Thanks.

[nabdelgadir]

@nabdelgadir , i think we'd still want users to open bugs/features for connector specific issues in here instead of against the loopback-next repo. So maybe we can use PR https://github.com/strongloop/loopback-connector-mongodb/pull/551/files as a reference? Thanks.

@dhmlau This one's using the connector specific one, but I have to update the mongodb one instead. nvm I see what you mean. I'll update this to match mongodb 👍