fix: set active database from query

[alespour]

For InfluxQL metaqueries to work with Cloud Serverless, active database needs to be set (via db HTTP query parameter). Current version only supports settings active via USE clause.

This PR adds sets active database using value of ON clause if present in the query and no db was set with USE.

• CHANGELOG.md updated with a link to the PR (not the Issue)
• Well-formatted commit messages
• Rebased/mergeable
• Tests pass

[bednar]

Thank you for your PR! 👍 Before we can proceed with accepting it, there are a few requirements that need to be met:

The InfluxDB v1 allows the creation of database names with spaces. We should also cover this use case:

[bednar]

LGTM 🚀