Redo "Revert "Deprecate String>>asDate"

[guillep]

Redo #15152, originally reverted because there are still broken tests.

Date>>asDate is ambiguous regarding how to interpret the day, month and year fields. Sometimes it interprets them in some order and sometimes in other.

'1-13-04' asDate => 13 january 2004

'13-1-04' asDate => 13 january 2004

Recently an exception was added in one of the cases above, but the ambiguity remains.
We propose with @guillep to deprecate it in favor of #readFrom:pattern: with an explicit pattern.

We deprecate methods:

• String>>asDate,
• Date>>fromString, and
• Date>>readFrom.
  Remove related tests on the deprecated methods.
  Use Date>>#readFrom:pattern: specifying a concrete pattern instead + all other.

We also added an option into the pattern parser to continue parsing using the continueAfterParsing method.

[guillep]

I got this change because of a merge. @jecisc do you know why?

[jecisc]

I have no idea where those "classSide" are coming from.. I've see it in the past in some projects but I never discovered why.

I never do my merges with Pharo, maybe it's the Pharo merger that uses another printer?

[guillep]

Strange, I have lots of tests failing that look unrelated to my changes, and look more related to the handling of protocols and extension methods, any idea?

[guillep]

They work in my local image based on build 1020.

Pharo 12.0.0
Build information: Pharo-12.0.0+build.1020.sha.373a7ce1fe48d19844129ab9086329fcf758ce50 (64 Bit)

[jecisc]

This is a known failure I'm working on that appears really recently: #15282

The error is really strange because it happens when updating the users of a trait, but the trait is generated in the tests and has no user (:

I'll try to fix it this week

[guillep]

Oh! Not my fault! Then I can remove the WIP from this PR :)

[guillep]

Why closing it instead of merging it?