Make Matte icon-library agnostic

[ksiabani]

At the moment, Matte is based on the library React-feather to show icons in some of its components. As a result:

• React-feather library is installed as a dependency to every project that Matte is installed
• People cannot use their own icon libraries, hence a design inconsistency occurs

What to do?

IMO we should:

1. Let people pass their own icons as props, and
2. Use SVG equivalents as defaults when people don't want to pass their own icons
3. For cases where an X icon is used as a way to close a window the × equivalent may be used (see implementation for Dialog component for this)

Who uses it at the moment?

See the list above to check the progress of replacing Feather icons:

• Table
• EmptyState
• Select
  - [ ] Layout - layout will be removed, see Deprecate layouts in favour of example layouts #44
• Metric
• Sidesheet