Dashboard: Improve Variable Handling Logic

[proy30]

With the addition of PR #921, the dashboard’s import parser must be updated to support loading variables from user-uploaded .py input files.

Only numerical (int and float) variable references are supported (ie. no math expression allowed or a reference to a function). Example: The dashboard will load in x = 50 and x = 3.14 but not x = '50' or x=5 + 5 or x=some_function()

TODO:

• [x] Load only the variables references in the lattice configuration section

  • Since we give the option of only utilizing the variable handler in the lattice configuration section.
  • A variable defined in the imported .py file but not used specifically in the lattice configuration build is not loaded in.

• [x] Allow users to negate variable values

  • For example, if ns = 50 allowing -ns would mean -50. Right now the dashboard does not support it.