Generate data for the new locode package

[roman-khimov]

Is your feature request related to a problem? Please describe.

I'm always frustrated when I'm looking at how NeoFS deals with locode DB. A binary (arch-dependent, btw) DB is needed for IR to work, no one knows where to get it from, no one knows what's inside, we have a lot of excessive logic around it.

Describe the solution you'd like

Rework DB generator to produce a set of simple CSV text files:

• countries: almost the same as original, but optimized to just code and name values (https://pkg.go.dev/encoding/csv#Writer will also drop quoting in most of the cases)
• continents: byte (a single char) and name values
• locodes: country code, location code, location name, continent code, subdivision code, subdivision name, latitude, longitude

These text files will then be reused by a new locode package.

Depends on #15.

[roman-khimov]

Seems to be done, isn't it?