schemas/vegbien.sql: added query_view_relation_max_prefix_len()

fix: schemas/util.sql: drop_relation(text), rename_relation(text, text): appended _esc to params that should be passed in escaped, and _name to those that shouldn't

bugfix: schemas/util.sql: rename_relation(): need quote_ident() around to_

bugfix: schemas/util.sql: truncated_prefixed_name_regexp(): need to match the entire string, so that the regexp can be used with util.replace_suffix()

bugfix: schemas/util.sql: truncated_prefixed_name_regexp(): need to pass max_prefix_len to util.name_was_truncated() because although the name itself might not have been truncated, it might become truncated once prefixed

schemas/util.sql: name_was_truncated(): support max_prefix_len param to determine truncation of something that will be prefixed

fix: name_was_truncated(): should use util.namedatalen() instead of hardcoding the value

schemas/util.sql: replace_suffix(): support strings that have been truncated (eg. as a table name) due to the prepending of a prefix

schemas/util.sql: added truncated_prefixed_name_regexp()

schemas/util.sql: added rtrim_n()