Troubleshooting docs

[nathanosdev]

Add a troubleshooting doc to cover common failure scenarios that have been encountered by the community:

• https://forum.dfinity.org/t/pocketic-picjs-server-busy-error/37790/4
• https://forum.dfinity.org/t/pic-js-pocketic-specified-canisterid-is-not-hosted-by-subnet/36105
• https://forum.dfinity.org/t/announcing-picjs-typescript-javascript-support-for-pocketic/24479/99 (search through the whole thread for failures)
• https://forum.dfinity.org/t/help-with-pocketic-intercanister-calls/32517
• https://forum.dfinity.org/t/how-can-i-see-console-output-when-testing-with-pocketic-jest/32964
• https://github.com/hadronous/pic-js/issues/76
• issues with dates far in the past (not related to NNS state)
• Reported test running time doesn't include beforeEach or beforeAll?
• https://github.com/hadronous/pic-js/issues/76#issuecomment-2655703567