Frontend: G14 breaking changes

This issue is a place for frontend platform to keep track of any frontend breaking changes we'd like to make for Grafana 14.

• remove TableInputCSV (no internal or external usage)
• clean up https://github.com/grafana/grafana/blob/main/packages/grafana-data/src/types/plugin.ts#L112
• finish removal of SCSS (see https://github.com/grafana/grafana/issues/64129#issuecomment-2338032974)
• move all MT plugins related apis from unstable.ts to index.ts
• remove MatcheID enum from grafana/data (see https://github.com/grafana/grafana/pull/124790)
• remove QueryField and related slate dependencies (https://github.com/grafana/grafana/issues/132401)
• remove MutableDataFrame (see #132648)