Amend the readme

[Finesse]

• Remove an unused image
• Split the description from the accuracy note. I think it's important to have a simple answer to a "why may I need this" question. A single short paragraph is used for this.
• Move a link to a React usage example from the Pro section to an OSS section. Also change the icon to an emoji resembling React logo.
• Stick to the common file naming style
• Add timestamps to the Pro response example
• Hide a Pro response example under a spoiler, because it's bulky, and an example is already given on the Pro picture
• Change "FingerprintJS Pro" to "Fingerprint Pro"

[Finesse]

@makma Do you want to take a look before I merge?

[makma]

Thank you @Finesse, looks good to me.