Enhanced Model catalog display

[anamika-yadav99]

Issue #12
I have improved the model display according to discussion in comment #12 (comment)

I have added a function to slice the catalog table into table of 15. Table size of 25 was huge.
I have also added ersilia catalog --next and ersilia catalog --previous in cli which displays the next and previous table consequently.
I have done so by storing a variable called counter in an auxiliary file which is initialized to 1 everytime ersilia catalog is called. Whenever ersilia catalog --next is called the counter is updated by 1 and displays the next table. Vise versa happens in ersilia catalog --previous. Counter is decreased by 1.
Implementing this was a little tricky due to all the corner cases of reaching the last table or ersilia catalog --previous on the 1st table. So, I have set the value of counter to 1 every time the table is on the 1st page. The user is informed about the last page table. The counter is decreased by 2 when on the last page in order to not display the same page. I hope all the corner cases are covered.

This is how it looks. Table size of only 5 was used here because ersilia hub has only 21 models, which made it hard to check for the corner cases:

[Rufaida98]

@anamika-yadav99 nicely done 💯

[anamika-yadav99]

There were a 2 bugs before. Which I have fixed now.

1. The counter would keep updating even after the table was ended which returned error on command ersilia catalog --previous and also if user did ersilia catalog --next
2. The initialize function was run even when --next or --previous command were used.

@miquelduranfrigola Could you please review this and give me your feedbacks

[anamika-yadav99]

@anamika-yadav99 nicely done 💯

Thanks @Rufaida98

[miquelduranfrigola]

This looks very good! Approving