2.0 cleanup list

[robertbastian]

• Unreadable inversion list JSON deserialization (Readable JSON inversion lists #2855)
• Remove support for legacy collator naming (sv_reformed_meta.toml)
• Remove any.rs from databake provider generated code
• Remove the definition of BakedDataProvider, instead favoring direct invocation of the macros (may need discussion)
• Remove icu_datagen/legacy_api
  • Remove extra segmenter data from icu_datagen (Remove hardcoded segmenter data from datagen #3003)
• CPT::get_ranges_for_value should be iter_ranges_for_value
• TrieValue::to_u32() should not be default-impl'd
• make properties set/map/script/etc from_data private or hidden
• Remove the icu_datetime_experimental feature from the icu metacrate (Address features in metacrate #3094)
• Organize properties code to be more like the other crates (get rid of free functions) #3573
• DateTimeFormat symbols data:
  • Look into replacing flat DateTimeSymbols arrays with VarZeroVecs #3599
  • Split DateTime symbols data into length-based chunks #3598
  • Should also consider splitting along symbol type
• calendar year/month methods:
  • Methods for getting formattable month/year should be called as such
  • FormattableYear should use NonZeroU8 for cyclic
  • FormattableMonth should consider dropping ordinal or using something else.
• Japanese's try_new_date/time() should have a _with_calendar() and another baked version should be added that doesn't need the calendar parameter.
• Find any #[deprecated] functions and remove them
• Remove mutable method on Ethiopic, potentially split calendar types
• Make capi baked data constructors the "normal" ones
• Upgrade to regex automata 0.3 (Updated regex-automata to 0.3 #3655)
• RangeBounds references: CodePointInversionListBuilder should take RangeBounds by valie #3678
• Make icu4x-datagen CLI --fallback default to Auto
• FFI
  • Move everything to HIR
  • Move everything to renamed namespaced APIs
  • Get rid of high-level FFI suffixed options structs in 2.0 #3791
  • FFI CodePointRangeIterator is missing ICU4X prefix #3851
• Encapsulate DataKeyMetadata::{fallback_priority, extension_key, fallback_supplement} in a DataKeyMetadata::fallback_config
• Consider making AbstractSerializer not use trait objects for the FsExporter in datagen
• Fix name of DateTimeError::UnsupportedField
• Remove variants of DateTimeError that are unused, such as Format
• Stop exporting icu_datetime::CldrCalendar or mark it as "not intended to be implemented"
• Delete strict_cmp_iter and SubtagOrderingResult in icu_locid (and any other deprecated APIs)

[Manishearth]

Properties cleanups:

We should remove all of the free functions:

• Binary property functions should go on CodePointSetData or whatever
• Enumerated property functions should live on the relevant property