feat: add dependabot config for go dependencies

[kruskall]

Motivation/summary

Add dependabot config for go dependencies.

Bump dev dependencies weekly and core dependencies daily as they are more important.

Dependencies are grouped together to avoid too many PRs.

Closes #12268

Checklist

• Update CHANGELOG.asciidoc
• Documentation has been updated

For functional changes, consider:

• Is it observable through the addition of either logging or metrics?
• Is its use being published in telemetry to enable product improvement?
• Have system tests been added to avoid regression?

How to test these changes

Related issues

[mergify]

This pull request does not have a backport label. Could you fix it @kruskall? 🙏
To fixup this pull request, you need to add the backport labels for the needed
branches, such as:

• backport-7.17 is the label to automatically backport to the 7.17 branch.
• backport-8./d is the label to automatically backport to the 8./d branch. /d is the digit.

NOTE: backport-skip has been added to this pull request.

[simitt]

Sorry for being late to this, has it be considered how the apm-server changelog updates should be handled with this? As the go-docappender and apm-data often contain logical changes relating to user facing features, I wonder how we can keep the changelogs up-to-date.