Add, train, test and resources pages UI

[microbit-grace]

What this PR includes

• Add data UI
• Train model UI
• Test model UI
• Resources UI
• Compatibility warning dialog
• Existing data loss dialog and logic

TODO

• Show accelerometer data in live graph
• Need to store bt pattern??
• Store microbit name and device Id, but don't keep device id because that's confusing
• Draw recording lines in live graph
• Error connection cases logic: https://paper.dropbox.com/doc/Reconnect-scenarios-copy--CTKwX5AyHNMod6Uq0Qosp8ZtAg-RWeX90ac5YQ9erncFZmWN can be used as reference
• Replace record data stubbing with real recording of data
• Record data button focus for the very first recording does not return to record button

Not worth doing

• Redirect dialog users to nextgen
• Sign up dialog
• Translation of resources page. We might be moving to using Sanity integration.

Things to note

• Performance warning dialog is coded but not used: https://github.com/microbit-foundation/ml-trainer/blob/main/src/components/dialogs/PerformanceWarningDialog.svelte#L1-L46 though it is documented in the reconnect scenarios paper doc (very bottom of page)
• Certain support links are not replaced and still have placeholder URLs

  ml-trainer/src/components/dialogs/UnsupportedMicrobitWarningDialog.svelte

  Line 23 in 148eb97

  // TODO: Replace with real support link.

Things I am unsure about

• Terminologies (gesture vs action vs class... etc., confidence vs. certainty, recognition level vs. threshold, prediction vs. estimated action) - aligning UI terminologies with namings
• What to do with existing gesture data stored in people's local storage from using prev version - migration code vs. accept that people will lose their data?
• The structure of the react hooks - are the connection hooks all a little confusing? What about the names? Connection flow vs. connection process

Other bits are commented inline in the diff

[github-actions]

Preview build will be at
https://review-ml.microbit.org/add-data