CLDR-15034 kbd: cherry picks from main

[srl295]

Two PRs that were merged to main (45) instead of maint-44.

Asking for a rubber stamp here to keep the branches consistent.

CLDR-15034

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• CLDR-17113 kbd: element/attr renaming (CLDR-17113 kbd: element/attr renaming #3313)

• CLDR-17113 kbd: element/attr renaming

- layers/@form > layers/@formId
- key/@flicks > key/@flickId
- key/@switch >  key/@layerId
- key/@to > key/@output
- display/@to > display/@output

• updates to dtd, samples
• drop some old data in tests

• CLDR-17113 kbd display output= and display= should support variables

• CLDR-17113 kbd shuffle element deck chairs

• longPress, multiTap now use a new keyList id
• keyList is a list of keys, has a default key
• flickSegment now uses a keyId instead of output

This means that each part of longPress, flick, and multiTap can:

• have a customization
• perform a layer switch if desired

Also, document.

• CLDR-17113 kbd: move keyList back into attributes

• CLDR-17113 kbd: add longPressDefaultKeyId

• replaces longPressDefault=true

• CLDR-17113 kbd: no nested gestures

• CLDR-17113 kbd: no nested gestures,2

(cherry picked from commit 5f1d298)

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• CLDR-17140 kbd: specify modifier matching (CLDR-17140 kbd: specify modifier matching #3314)

• CLDR-17140 kbd: specify modifier matching

• CLDR-17140 kbd: rename modifier= to modifiers=

• CLDR-17140 kbd: modifiers: add 'other' and comma

• now supports modifier 'other' if nothing else matches
• now supports comma-separated lists of modifier sets
• attribute name "modifier" changed to "modifiers"

• CLDR-17140 kbd: remove extraneous mention of duplicate keys

• per review

• CLDR-17140 kbd: modifiers review comments

(cherry picked from commit 286a10b)

CLDR-_____

• This PR completes the ticket.

ALLOW_MANY_COMMITS=true

[srl295]

I'll need to cherry pick #3330 also, which can be a separate PR if that one isn't merged by the time this one's review'd.