Deprecate binary, trinary, octal, and hexadecimal in favor of new all-your-base exercise

[kytrinyx]

We've settled on replacing the four almost identical exercises with one that is more interesting and comprehensive, which converts a number in an arbitrary base to the equivalent in a second arbitrary base. See #276 for details.

We need to (I think):

• wait for the pull request that adds all-your-base to be accepted
• finish working out the process for deprecating exercises in Formalize the process for deprecating exercises discussions#40
• add a .deprecated file to octal
• add a .deprecated file to hexadecimal
• add a .deprecated file to binary
• add a .deprecated file to trinary
• draft the text for a new issue that can be submitted to all the languages (see https://github.com/exercism/blazon#tips)
• submit the issue using blazon
• wait for all the related issues to be closed
• close this issue

[kytrinyx]

FYI @rbasso @NobbZ @ErikSchierboom @wobh @Cohen-Carlisle @yurrriq

Before we can submit a blazon ticket we need to finish clarifying the process for deprecating exercises. Up until now it's been messy and prone to error, and I'd rather have that all straightened out before we deprecate four at a time across a bunch of language tracks. exercism/discussions#40

I've updated the checklist in the original post of this issue to reflect what I think we need to do to get this all sorted out.