Add default aidbox alchemy func definitions

[ruscoder]

Let's make them available via sqlalchemy.func by default (project independent):

• knife_extract_text
• knife_extract_max_numeric
• knife_extract_min_numeric
• knife_extract_min_timestamptz
• knife_extract_max_timestamptz
• knife_date_bound
• aidbox_text_search

@ir4y What do you think? They can be useful for custom endpoints with sqlalchemy.