Fix and Improve veBAL section

[Xeonus]

In the current state, veBAL will be also used with Balancer v3 incl. the gauge system. Therefore, we need to keep this section up-to-date.

Identified issues with current docs:

1. no introduction page outlining / explaining the veBAL concept
2. organize math / technical sections for APR and boost calculation
3. Add more info for boost delegation and other missing features
4. Fix legacy wording that boost is only possible on L1s

[Rassska]

@mkflow27.

Can i work on this?

• I wanna create animations using manim to break down some math behind. It'll be easy to follow.

• Although, i didn't do similar work in web3, but have worked with manim a lot, some testing work that i did: https://www.youtube.com/watch?v=P4Z9XdHAE4o&t=654s

• Also, what do you think will be great to cover with animations? Some heavy math parts in docs?

[mkflow27]

@Rassska Thanks for tagging me. Sure. What I read from your message is that your intention is mainly to use Manim for math animations rather than specifically address the points mentioned by @Xeonus. Can you elaborate a bit which animations you could see being useful for this ticket? Describe their content for example.

[Xeonus]

The intention of this ticket is to improve the current docs that we have specifically the points I raised. @Rassska feel free to work on this and propose a PR from fork, although I can't see yet what you exactly intent to do / what is the value add and we shouldn't introduce too many heavy package dependencies IMO.