AnkiMobile card links open in browser and added link disabling option

[qappell]

Summary of changes:

• Lets AnkiMobile clients use URL scheming to open note links in the AnkiMobile browser.
  • Flow to check each client: check for AnkiMobile → else initialize AnkiDroidJS API → if error, use AnkiWeb link
• Added a variable to toggle link rendering on or off. (jumpToAnkiWeb is no longer necessary with functionality for all clients)
• Updated and clarified steps and explanations for new code.

Tested and observed perfect operation of link rendering on AnkiWeb, AnkiDroid, and AnkiMobile (iOS).

README-zh.md is not yet updated with code nor explanations.

[gugutu]

Thank you!