[4.0] Clean up com_users forms

[SharkyKZ]

Fixes #30794.

Summary of Changes

Removes form field layout override.
Removes useless descriptions from Profile plugin.
Removes use of non-existing strings.
Adds "strength meter" to password reset form.

Testing Instructions

Inspect all forms in com_users.

Actual result BEFORE applying this Pull Request

In user profile form, the description for Username field is missing.

Expected result AFTER applying this Pull Request

Mostly looks the same, but Username field in profile form now has a description: If you want to change your username, please contact a site administrator..

Documentation Changes Required

No.

[ceford]

I have tested this item ✅ successfully on 5e98b7d

All the forms I looked at seemed normal. The Username description was present.

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[ohrionmartin]

I have tested this item ✅ successfully on 5e98b7d

System Information

php: Linux orion 5.4.0-48-generic #52-Ubuntu SMP Thu Sep 10 10:58:49 UTC 2020 x86_64
dbserver: mysql
dbversion: 8.0.21-0ubuntu0.20.04.4
dbcollation: utf8mb4_0900_ai_ci
dbconnectioncollation: utf8mb4_0900_ai_ci
dbconnectionencryption:
dbconnencryptsupported: true
phpversion: 7.4.3
server: Apache/2.4.41 (Ubuntu)
sapi_name: apache2handler
version: Joomla! 4.0.0-beta4 Beta [ Mañana ] 15-September-2020 13:46 GMT
useragent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:81.0) Gecko/20100101 Firefox/81.0

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[Quy]

RTC

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[zero-24]

Merging thanks.