Gorm: add Context

[koalacxr]

Support Context :
BeginTx(ctx context.Context, opts TxOptions) (Tx, error)
ExecContext(ctx context.Context, query string, args ...interface{}) (Result, error)
PrepareContext(ctx context.Context, query string) (Stmt, error)
QueryContext(ctx context.Context, query string, args ...interface{}) (Rows, error)
QueryRowContext(ctx context.Context, query string, args ...interface{}) *Row

[posener]

I think this duplicates #1231

[alexsn]

That's from 2 years ago, is gorm never gonna support context? Are we waiting for a PR or is there a general objection to add context support?

[penguinpowernz]

Seems like there is some movement over there with some code available to be merged... let's close this and track it in #1231