Feature/sc 76870/ mindsdb google ads integration

[gabrielbressan-tfy]

Adds a new google_ads integration handler that connects to the Google Ads API via OAuth2 (refresh token flow).

Tables

Table	Description
campaigns	Campaign metadata (name, status, budget, channel type)
ad_groups	Ad group metadata linked to campaigns
ads	Responsive search ads with headlines and descriptions
keywords	Keywords with match type, quality score, and bid
campaign_performance	Daily metrics per campaign (impressions, clicks, cost, CTR, CPC, CPM)
search_terms	Search term performance with daily breakdown

Notes

• campaign_performance and search_terms require start_date/end_date in WHERE; default to last 30 days when omitted
• All tables follow Pattern A: fetch full data from API, let DuckDB handle aggregations and complex expressions
• campaign.start_date and campaign.end_date removed from the campaigns GAQL — they are not valid fields in the Google Ads API