Introduced different key stores for LE secure, using json file or NVS

Version 2

- Micropython version 1.20+ bugfix
- Enabled bonding
- Enabled BLE secure
- IRQ handles read requests properly
- IRQ handles MTU properly
- Improved documentation

Added examples to use asyncio

Added TinyPICO specific examples
Updated readme

Merge pull request #1 from Heerkog/add-license-1

Create LICENSE