Similar in spirit to my previous changeset, #155583386, this is an effort to reduce import cruft on the Missouri state highway network.

The tags deleted in this changeset are 100% redundant. For example, if tiger:name_base_3=foo and name_3=foo, then the former is deleted. But if name_3=bar, then tiger:name_base_3 is kept. By focusing just on name_base, this doesn't even attempt to do anything with directional affixes (which, side note, are frequently incorrect with MO supplemental state routes)