Uncrispify AccountForm in useradmin

[johannaengland]

Closes #3135.

This is quite a bit more complicated of a refactor. So I would suggest reading it commit by commit.

The form can look four different ways:

1. Creating a new user: login, name, password fields are empty and read&write, submit field says "Create account"
2. The default user - only the name can be changed, login and password fields are greyed out/read-only
3. Normal user - similar to a new user, all fields are read&write, but have current information in them when loading and submit field says "Save changes
4. Externally managed user (e.g. ldap) - only login and name are visible, but login read-only, has an additional blue info box "External authenticator: {{ authenticator }}"

Urls (when using a dump of the sikt-vk):
http://localhost/useradmin/account/new/ (1. New user)
http://localhost/useradmin/account/0/ (2. Default user)
http://localhost/useradmin/account/1/ (3. Normal user)
http://localhost/useradmin/account/1093/ (4. External user)

As already in the code suggested I split these forms up into two different forms: AccountForm for use cases 1-3 and ExternalAccountForm for use case 4.

@podliashanyk and I made the decision to move the blue "External authenticator" box to the top of the fieldset, that made it much easier to override the template and makes it look more cohesive

Screenshots of that change:
Previously:

Now:

[github-actions]

🦙 MegaLinter status: ✅ SUCCESS

Descriptor	Linter	Files	Fixed	Errors	Elapsed time
✅ PYTHON	black	992		0	11.38s
✅ PYTHON	ruff	987		0	0.1s

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Test results

    9 files      9 suites   8m 51s ⏱️
2 138 tests 2 138 ✅ 0 💤 0 ❌
4 015 runs  4 015 ✅ 0 💤 0 ❌

Results for commit 4d8eea0.

♻️ This comment has been updated with latest results.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 60.38%. Comparing base (3f0faab) to head (4d8eea0).

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #3168      +/-   ##
==========================================
- Coverage   60.39%   60.38%   -0.02%     
==========================================
  Files         605      605              
  Lines       43704    43699       -5     
  Branches       48       48              
==========================================
- Hits        26396    26388       -8     
- Misses      17296    17299       +3     
  Partials       12       12              

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Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

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