Add more installation details for users new to Julia

Specifically, this instruction,

Lines 15 to 19 in 9f5b4b9

    
           ## Quick Installation 
        
           To install the package, use the following command: 
        
           ``` 
        
           julia>]add GIRFReco 
        
           ```

was not clear to me as someone with only a little Julia experience (and last time I used it was a few years ago).

Because, "use the following command" usually means "copy and paste this" into the terminal/software, and this command as is doesn't work in neither the mac Terminal or the Julia session. Even copy pasting ]add GIRFReco doesn't work once inside the Julia terminal; you need to explicitely type it because typed ] opens the julia package manager but copy-pasting "]" with a command doesn't.

I'd recommend breaking it down into three instructions.

Open a Julia session
Open the package manager by typing ]
Add the package using the command add GIRFReco once in the package manager.

Good point, even though I'd recommend not expanding the help here, because if every package does that for every of the installation steps it's longer to read for the ones who know how it works (+repetition). How about putting a link to the official julia manual, there is a chapter on the package manager. That would be a one-liner and point beginners in the right direction.

Here

GIRFReco.jl/README.md

Lines 16 to 19 in 9f5b4b9

    
           To install the package, use the following command: 
        
           ``` 
        
           julia>]add GIRFReco 
        
           ```

I could imagine something like [To install the package from the julia REPL](https://link.to.manual/packagemanager) use:

Thats fair! I think at a minimum, if hou’re going to say ] and the command in the same line, the instructions should be to type it (to avoid copy-pasting issue like I had, very few ppl in MRI are using Julia atm, see my editorial in MRM https://onlinelibrary.wiley.com/doi/10.1002/mrm.29366)

@mathieuboudreau There is an explicit Julia-n way to do this which avoids the copy paste confusion. Some packages include it, but we elected not to. I will add it for clarity. The copy and paste friendly version is:

using Pkg
Pkg.add("GIRFReco")

Hi, maybe I can give my grain of salt on this. If you copy and paste this line in the Julia REPL

(@v1.9) pkg> add GIRFReco

It just works 😎 . At least in Linux and Mac, not quite sure about Windows. I agree with @mathieuboudreau
that the word type is fundamental for the ] add GIRFReco instruction. In our experience with students with 0 Julia experience saying "type ]add Package in the Julia REPL" was enough for them to install the package successfully.

As @felixhorger said, I would not put so much information in the README.md, and would refrain from using Pkg as it gives the impression to new users that it is more complicated than it actually is.

If you want to give additional instrucctions (nothing wrong with that), you could add a Getting Started section in the documentation

Addressed in daa1608

	## Quick Installation
	To install the package, use the following command:
	```
	julia>]add GIRFReco
	```