Inconsistent naming in the application

1) The application is called Elements Core but shows Liquid logo, would benefit from standardisation to avoid confusion.
2) When running `Liquid Core` for first time, dialog says `welcome to Elements Core`, and tells me that it will download and store a copy of the `Bitcoin block chain` - pretty sure this is referring to Liquid blockchain - this is obviously very confusing. Liquid is not even mentioned.
3) Same dialog box says the `Bitcoin blockchain` is 1GB big, containing transaction data from 2009 - specific naming of blockchain size seems risky if not dynamically generated, will go out of date quick.

I was downloading Liquid binaries, so expected to see application called Liquid Core, and dialog reference to the Liquid block chain (sidechain).


Version: liquid-0.17.0-osx-unsigned.dmg

Start by reproducing the first-run dialog from liquid-0.17.0-osx-unsigned.dmg and inspect the GUI branding and text resources it uses. Done means the application and dialog consistently identify Liquid Core and the Liquid sidechain, without relying on outdated hard-coded Bitcoin blockchain details.

Written by the indexing model from the issue text.