crypto/tls: Expose maps for cipher suite IDs/names

[JAORMX]

These are utility functions that allow you to get maps that translate from Cipher Suite names towards IDs and vice versa.

The main purpose of this is to be able to easily parse such configurations for HTTP(s) servers without much boiler plate code.

Fixes: #30325

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[gopherbot]

This PR (HEAD: 6d13a8f) has been imported to Gerrit for code review.

Please visit https://go-review.googlesource.com/c/go/+/163119 to see it.

Tip: You can toggle comments from me using the comments slash command (e.g. /comments off)
See the Wiki page for more info

[noneymous]

Thank you @JAORMX for this pull request, Having this change would be awesome.

I often have problems in GO where some go packages holds some information I'd like to access, but I can't because its private and there is no way araound. Okay, technically, in this case the data is accessible, but not in an dynamic way. I need to know the constants and i cannot just query them.

This really sucks. From a builders point of view I understand, that some information is not necessary and can be unknown. But i do use Go for testing (respectively, building security checks), and such information is elemntary to me.

I have a similar problem with the SSH package. It holds information about what cipher suites are supported by a remote server, but I can't access it ^^

[JAORMX]

@noneymous thanks for checking this out! Feel free to jump in #30325 where the discussion about this is happening.