Docs: Security Best Practices for Cadence

[alxflw]

Take content from https://github.com/HalbornSecurity/Security-Best-Practices-for-Cadence-Developers-Flow-

and merge it into the Cadence section (https://docs.onflow.org/cadence/), likely best as a new page

[bluesign]

I think this is too brief ( not diving in to detail ), in my opinion it can have very bad influence on developers. We already have low composability, this suggestions will kill it a bit more.

Also some stuff like e.g. re-entry, getType() behaviour should also be mentioned. I would love to have some examples (cadence code) in those items to illustrate new users how vulnerability can happen.

To be totally honest, some items even I ( as familiar with the security concepts), had to re-read to understand.

[alxflw]

@franklywatson it seems the content here needs more discussion. @wise4rmgod could help get it onto the docs page but let's make sure we iterate on the content. can you please response to @bluesign feedback?

[alxflw]

hey @bluesign - we've discussed your feedback and decided to get a first version of this onto the docs right away + iterate on it later. this content is adding value and given our limited resources to improve it right now, we will have to address some points either later. if you have the ability to improve it based on your suggestions, a PR would be very welcome. thanks!