[Discussion] Add method to force loading Templates into memory

[h-mayorquin]

Discussion PR. @samuelgarcia @alejoe91

Following on https://github.com/SpikeInterface/spikeinterface/pull/2828 and as alternative to the code in #2436.

With this, if you are in a scenario (I guess like plotting?) where you are going to be making repeated calls to the functions then you can call this function. We can even add an argument to the signature and call this at post_init.

The advantage of this vs loading by default is that the __init__ of the object becomes lighter at the cost of some complexity.

What do you think?