Generic blackboard implementation

[kaphula]

Generalize blackboard.

From user's perspective, in addition to being able to use generic blackboard type, the user must now use tick directly with bt.tick(...) instead of bt.state.tick(...) This change is required so that we can pass a mutable reference of the blackboard to the user's tick callback under the hood.

[Sollimann]

Will try to find time to review tomorrow👌

[Sollimann]

Added a nit comment, other than that it looks good to me :) Great work 👍 Can merge after fixing the nit comment.

Also, another nit comment:

Are you currently able to branch out from this repo? if not, let me know and I will try to fix it in the repo settings. It makes it easier to inspect / collaborate on a PR if I can just git checkout your branch without having to clone the repo from your github.

[Sollimann]

nit: I believe this can be private i.e remove the pub keyword

[kaphula]

Hey, thanks for the review! I pushed the branch to your repository, should be there as generic-blackboard. Is that what you meant?

As for privating the SequenceArgs, I am not sure how this could be done because the struct must be used upon calling sequence function at state.rs. I had to create this struct because pre-commit prevented me from using too many arguments otherwise.

[Sollimann]

@kaphula Yea, that's what I meant. Thanks! Sorry, I didn't see that it was used in another file. You can make it pub(crate) instead to make it clear that it is used internally only.

[kaphula]

Alright, that's done.