591 fix remove extra layer on variables in construct and ensure variables can be referenced in

[johbaxter]

How to test:

Step 1.
While on the dev branch, I created old apps based on the apps that were built on workshop dev. I grabbed the json from there and pulled them into my local. Did this for about 10 apps.

Step 2.
Switch to the branch tied to pull request and ensure the old state hits my migration function as intended.

Resolves #18

[johbaxter]

Things that were completed in this PR:
DONE: Migrate old syntax {{block.input-2712.value}}, {{query.python_code.cell.92121.output}}, {{query.python_code.output}} to variables
DONE: variables that are cells --> "queryId": "", "cellId": "", We don't want to do string manipulation to get left and right pointer
DONE: In designer only give variables as options with settings select
DONE: In designer, Selected and Hovered mask show variable name if it is a variable
DONE: rename cell allows creates a variable
DONE: rename block creates a variable
DONE: Fix Migration logic, If old app does not have version it's safe to assume they are at the first version
DONE: Ensure no duplicating variable names, all have to be unique (error message), check the renaming too TODO: TEST
DONE: Ensure periods can't be in alias (will mess with syntax perhaps)
DONE: Migration Manager, if pointer is already in variables don't create a variable just change it to whats already there.

I added a second test migration function that will show that it will run recursively until app is up to date. Just change the current version and you will see the state update.

old-vars.json

[neelneelneel]

Resolves #22