Update ReadME pages of all samples

[LeonArmston]

Hi @jameseccles and @jansenbe

I have updated all Readme files of all the Syntex Samples to add consistency with my submitted sample

Mainly adding

• Types section to table to explain type of extractor i.e. Regular Expression
• Sample section to give sample Author credit - I believe @jameseccles is author of all the samples but please do correct me if so? I do apologise!
• PnP Hidden Image for tracking- not 100% sure if this is set up for this Syntex repo but have added this to each page

  <img src="https://telemetry.sharepointpnp.com/syntex-samples/samples/Aviation Incident Report" />

Let me know if you have any questions or feedback. Feel free to correct or suggest improvements - I'm glad to help!

Thanks

Leon

[jameseccles]

Thanks for the contribution!