Consistent naming for auth/view lemmas.

See merge request iris/iris!533

add iff lemma for '✓ (to_agree a ⋅ to_agree b)'

See merge request iris/iris!535

Also rename the recently added `view_update_alloc_frac` into
`view_update_frac_alloc` to be consistent with other lemmas about the
placement of `_frac`.

Use infix `_frac` for the `●{q}` variants. This was already done for the
external validity lemmas, but not for those for inclusion and internal validity.

dfrac: do not track discarded fraction

See merge request iris/iris!531

Put `iProp`/`iPreProp`-isomorphism into `own` construction

See merge request iris/iris!530

Rename `cmra_monotone_valid` into `cmra_morphism_valid`

See merge request iris/iris!529

Add discardable fractions camera

See merge request iris/iris!497

expand auth changelog

Closes #353

See merge request iris/iris!528

The view camera.

Closes #257

See merge request iris/iris!516