Allow to forbid-list tables from generation

[vetcher]

Sometimes, database contain tables that is not relates to domain itself and are serving as technical information. So we want it to be ignored by jet.
E.g. applied migrations list (https://github.com/pressly/goose creates table goose_db_version)

I propose to add some flag to cli, so generator would ignore tables passed to this flag.

$ jet -ignore="goose_db_version;locks"

[go-jet]

Yeah, make sense. The flag should probably be -ignore-table, to differentiate from views, and enums.

[flymedllva]

LGTM

[go-jet]

New generator flags -ignore-tables, -ignore-views and -ignore-enums added in Release 2.7.0.