This module still holds old code and deserves some love. This commit cleans a
bit the init and manifest files as well as renaming view file according to
guidelines.

This commit is linked to task ID 1896681 and PR #27975. No functional change
should occur with this commit as it contains only renaming / move.

We would like to make the "no item found" screens more appealing.

Before this commit, it shows a small help tip in the top-left
corner of the screen, just below the "Create" button.

With this commit, these help tips have been replaced by onboarding
screens, which consist of a picture and some text below, both of which
are horizontally centered.

The texts have been slightly changed, so that they are shorter and clearer.

Considered modules:

(A)
    account,
    account_asset,
    account_budget,
    account_test,
    account_voucher,
    analytic
(B)
    barcodes,
    base,
    base_automation,
    board
(C)
    calendar,
    contacts,
    crm
(D)
    delivery
(E)
    event
(F)
    fleet
(G)
    gamification,
    google_drive
(H)
    hr,
    hr_attendance,
    hr_contract,
    hr_expense,
    hr_gamification,
    hr_holidays,
    hr_payroll,
    hr_recruitment,
    hr_timesheet
(I)
    im_livechat
(L)
    l10n_fr_sale_closing,
    link_tracker,
    lunch
(M)
    mail,
    maintenance,
    mass_mailing,
    membership,
    mrp
(N)
    note
(P)
    payment,
    point_of_sale,
    post_mercury,
    pos_restaurant,
    product,
    project,
    purchase,
    purchase_requisition
(R)
    rating,
    repair,
    resource
(S)
    sale,
    sale_timesheet,
    sales_team,
    stock,
    stock_account,
    stock_landed_costs,
    stock_picking_batch,
    survey
(U)
    utm
(W)
    web,
    website,
    website_blog,
    website_customer,
    website_event_track,
    website_forum,
    website_quote,
    website_sale,
    website_sale_digital,
    website_slides

When user click on the App 'Link Tracker' , it gives one view..
Here , there is a menu 'Link Tracker' > 'Tracked Links' , which gives
the same view, so we have to remove the submenu which is 'Tracked Links'.

Indeed UTMs should be created from the front end, via promote.

Also fixed some mismatch in tracker views by correctlin setting the view_id in
mass_mailing and classic utm view.