Docs: Fix documentation around target token limitations

[jnodorp-jaconi]

The documentation states this about target tokens:

https://github.com/eclipse-hawkbit/hawkbit/blob/37f2ceb8efda355c1cfdc6b9ee4337771846b4d7/site/content/concepts/authentication.md?plain=1#L25

This is wrong.

Target tokens can have up to 128 characters. I tested this and could not find any limitation when using a 128 character target token.

Also there is no limitation to alphanumeric characters. I tested base64 encoded tokens (containing =, -, and /) and could not find any issues.

Given that the limitations seem arbitrary, I'd suggest updating the docs instead of adjusting the code.

[denislavprinov]

Hi @jnodorp-jaconi,

Thank you for bringing this to our attention! We are currently in the process of migrating the documentation to GitHub Pages, and this update will be reflected in the new documentation.