Don't use user.manage permission for packet management permission checks

[david-mears-2]

canManageAllPackets is the name of functions that existed both in the front end and the back end, which allow users to manage packets when they have global user.manage permission (including when they don't have packet.manage).

We should keep packet management permissions separate from user management, so I have removed this function and replaced it with a reference to hasGlobalPacketManagePermission.

The exception to keeping the two scopes separate is when granting users packet-related permissions; that really is both user management and packet management. It looks like currently these actions are defended only by 'user.manage' (e.g. at the top of RoleController), i.e. through packit I can give someone (myself excluded) permissions for any packet, regardless of whether I have permissions for that packet. This seems OK but I wanted to check.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 99.26%. Comparing base (01427e2) to head (09979aa).

Additional details and impacted files

@@                         Coverage Diff                          @@
##           mrc-6905-show-installed-packages     #258      +/-   ##
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- Coverage                             99.26%   99.26%   -0.01%     
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  Files                                   203      203              
  Lines                                  5889     5887       -2     
  Branches                                983      981       -2     
====================================================================
- Hits                                   5846     5844       -2     
  Misses                                   42       42              
  Partials                                  1        1              

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[absternator]

The initial idea was to make user.manage kind of like a god permission. As people who can manage users can pretty much do anything in the application. Thus not having to add packet.manage or any other permissions to people who can manage users. As this probably the highest level permission.

The issue here is if they want to add permissions to a user with packets but dont have the manage permission then they cant add those permissions. Beacuse pretty sure they wont see the list of packets and packet groups anymore when updating permissions. This is not right: a user with user.manage should be able to add/remove any permission to a user without needing packet.manage. See screenshot below with a new user with only user. manage