[DESIGN] Implement changes to bidi to permit non-strict formation (#811)

* [DESIGN] Implement changes to bidi to permit non-strict formation

**_DO NOT REVIEW_**

This PR will eventually include the design changes. Currently a work in progress.

* Address comments plus update "other" solutions

Since we're adopting "loose" as the proposed design, put "strict" as a considered option.

* Edits to add some previous discussion points

* Typo

* Improve discussion of abuse

* Update bidi-usability.md

* Update bidi-usability.md

* Add the 'super-loose' option

* Update exploration/bidi-usability.md

Co-authored-by: Eemeli Aro <[email protected]>

* Update exploration/bidi-usability.md

Co-authored-by: Eemeli Aro <[email protected]>

* Address comments, add Postel's Law design approach

* Update exploration/bidi-usability.md

Co-authored-by: Tim Chevalier <[email protected]>

* Commit @eemeli's comment

Adding this text in, to be followed with some of the discussion from the PR

Co-authored-by: Eemeli Aro <[email protected]>

* Add missing ABNF

* Add discussion points

Adding the pros/cons for isolating name tokens in order to facilitate discussion.

* Address comments from @catamorphism

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Co-authored-by: Eemeli Aro <[email protected]>
Co-authored-by: Tim Chevalier <[email protected]>

Author: 3 people