Rename web3 provider to Ethereum provider

[bbondy]

Description

Since windows.web3 is going away it doesn't make sense to call it a web3 provider anymore. We should call it an Ethereum provider.

New text: Ethereum provider for using Dapps

New text: Would you like to start Crypto Wallets for Ethereum support?

Test Plan

Just make sure chrome://settings in the Extension setting shows the right text. Also the infobar which comes up when you visit cryptokitties.co

[btlechowski]

Verification passed on

Brave	1.16.55 Chromium: 86.0.4240.72 (Official Build) dev (64-bit)
Revision	581582174c512f44f44fd1aea340471f54b2365f-refs/branch-heads/4240@{#1134}
OS	Ubuntu 18.04 LTS

Verified test plan from the description

Verified text was updated Ethereum provider for using Dapps in brave://settings/extensions:

Verified infobar on cryptokitties.co:

Verified Polish locale

[srirambv]

Verification passed on

Brave	1.16.59 Chromium: 86.0.4240.75 (Official Build) beta (x86_64)
Revision	c69c33933bfc72a159aceb4aeca939eb0087416c-refs/branch-heads/4240@{#1149}
OS	macOS Version 10.15.7 (Build 19H2)

• Verified brave://settings/extensions is renamed to Ethereum provider for using Dapps
  
• Verified setup info bar has the changed text Would you like to start Crypto Wallets for Ethereum support?
  

---

Verification passed on

Brave	1.16.59 Chromium: 86.0.4240.75 (Official Build) beta (64-bit)
Revision	c69c33933bfc72a159aceb4aeca939eb0087416c-refs/branch-heads/4240@{#1149}
OS	Windows 10 OS Version 1809 (Build 17763.1490)

• Verified brave://settings/extensions is renamed to Ethereum provider for using Dapps
  
• Verified setup info bar has the changed text Would you like to start Crypto Wallets for Ethereum support?