Review consistent use of 'initialise' over 'instantiate'

[romaricpascal]

What

Ensure our pages consistently use initialise, rather than instantiate, when referring to components initialisation in the v5 part of the documentation.

Why

Since v5.0.0, instantiating a component automatically initialises it. Using a consistent word for it will prevent users from wondering if they're different things or the same.

Who needs to work on this

Tech writers

Who needs to review this

Tech writers, Developers

Done when

• We've gone through the docs and checked we no longer use 'instantiate'/'instantiation' or other variations when talking about components initialisation