Add public registration API for Technic chests

[S-S-X]

See #117 and #117 (comment)

PR that updated registration to provide basic usable API is merged.

Things to do:

• Allow overriding functions.
• Allow overriding other fields.
• Also allow adding fields not known by technic_chests.
• See if there's existing functions that would be useful if exported to public API and add those.
  For example to be used when overriding some of default functions.
• Configuration for default chest registrations, select features and disable chest types.
• After this list is completed this should probably be standalone mod not included with technic modpack...

[OgelGames]

An issue really isn't needed when a PR to fix it is created at the same time...

[S-S-X]

An issue really isn't needed when a PR to fix it is created at the same time...

Like stated also on linked PR "API is not complete but more like starting point" pull request linked here is far from complete implementation, more is needed to make it complete.
It is also different from #117 and that issue has separate PR which is supposed to close it.

I think it is good to have issue as a reminder after linked PR is closed.
edit. should also remove closing keyword, will update that.