[Master] Improve / Fix Hero Academy

[Nexus1254]

As I already said here:

@Nexus1254

I stopped using HA for retraining legendary heroes long time ago. I have exactly one non-S1 hero - 5*, and not even planning on ascending him.

I’m currently making troops. I think HA needs to align with the other advanced buildings:

• have maximum 3 processes at the same time
• allow to have a queue - non only one by one

When those two will come to live, I’ll get back to HA 10.

When I stopped, I had like 25 retrainings, all S1.

I would really love to see those two changes on the Academy. I honestly don’t know why they would limit this building so much, considering that you need to have most of the buildings maxed before having the HA 10 + research done