Autocompletion for company names

[kangas]

Support efficient autocompletion of company and entity names. Related to search interface for index files (#10)

Rather than searching the quarterly/daily index files, it might make more sense to retrieve the "Current list of all CIKs matched with company name" ("cik.coleft.c") as noted on
https://www.sec.gov/edgar/searchedgar/accessing-edgar-data.htm

Note that this list includes funds and individuals and is historically cumulative for company names. Thus a given CIK may be associated with multiple names in the case of company or fund name changes, and the list contains some entities that no longer file with the SEC.