[TESTING] SLDS2 Icons on SLDS1 and Vice Versa

[JodieM]

We need to test SLSD2 Icons on standard SLDS1 record pages. And SLDS1 Icons on SLDS2 record pages.
Eg ALL the Custom Icons are now renamed and are circles only. and all the object icons are named differently

See SLDS2 Icons

Examples:
standard:new_account is a circle
standard:account is a square
custom:new_custom1 is a pink heart in a circle
custom:custom1 is an orange heart in a square

To Test:

• Can we mix and match new and old icons in the same bundlle
• How do old icons look in SLDS2
• Is SLDS2 a global change, not per user or permission set (I think so)
• Do the SLDS2 Icons override colours correctly
• Do the SLDS2 Icons act like an Avatar correctly.

We will then need to write up some documentation to note any differences - see #202 for that.