[contents] New properties for contents: ID, Position, Size, and Measurements

Agregar nuevas propiedades a los "contents" para que sean más flexibles.

ID

Unique identifier for the content.

Implementation ideas:

• Reuse the "name" property, forcing it to be unique in the workspace.
• Make a new property.

Related to #143 and #142, which would allow finding a content in the workspace when it is moved between platforms (e.g. by a gripper tool).

Position

Make the "position" of a content definable from either:

• Index of the "slots" in a platform (i.e. a "well index" in grid platforms).
• Col/Row of a grid-type platform (e.g. well plate or tip rack).
• XYZ position (e.g. for a colony).
• Name/ID of a "slot" in the workspace (#34 #100 (closed)).
  • Este dejarlo para más adelante, y repensarlo cuando estén implementados los slots.

Properties

Arbitrary properties for a content:

• Volume (the default, can be set by the left side panel).
• Other phisical, chemical, or biological properties should be "store-able" in the content (relates to #8). For example:
  • Turbidity.
  • Colour.
  • Conductivity.
  • Complex data (e.g. files containing other experimental results: microscopy images, videos, etc.).
  • ...
• These properties are likely very related to measurements from protocol executions from #8

Implementation ideas:

• Simple data could be stored in content tags (using a syntax similar to gitlab's scoped tags). For example: a turbidity (OD) measurement of 0.39 could be stored in a tag with text OD::0.39. This has the advantage of being flexible and editable without adding complexity to the gui.
• Add a button to each content that opens a text editor, and can be used to inspect it's properties.
• ???