[EGD-6168] Lock CPU frequency only while BT is working

Due to fixed BT transmission, the CPU frequency can be lower.
To be more power-friendly, minimal working freq is being set while
working with Bluetooth

[EGD-6259] Turn off usb security

To prevent errors with USB connectivity and charging screens.

[EGD-5744] Phone mode status bar widget

Added phone mode widget to top bar. The widget is mutually exclusive
with NAT widget. Phone mode is determined using phone mode observer.

[EGD-6455] Fix modem AT command timeouts

Fix modem AT command timeouts and make sure they are at least
bigger than the ones defined in Quectel specs.

[EGD-6455] Disable service audio debug loggs

They were too much of them

[EGD-6455] Fix for incomming text messages issue

There was no proper error handling.
Minor routine refactor

[EGD-6264] About Your Pure Main Window

Add window About Your Pure to help display Technical Information,
Certification and SAR.

[EGD-5783] Revert EGD-5783

Revert "EGD-5783 Exclude empty body from response message"
This reverts commit b64eb0622b6c5e59eeb2161223e793ba4164ceb9.

[EGD-6282] Add marketing-friendly test messages to Pure

Added a long 4K note from a book and Mudita-related.

[EGD-6282] Add marketing-friendly notes

Added a marketing-friendly notes and a 4K chars passage
from 'The Picture of Dorian Grey'.

[EGD-6277] Changed contacts to English names

Changed contact names and contact details to 
more marketing-friendly.

[EGD-5783] Exclude empty body from response message

Remove body field from response message,
if it contains null. Add 204 and 501 status codes
and use them in proper responses.
204 stands for success but no content, and 501
means endpoint is not implemented.
Additionally some minor fixes.

[EGD-4593] Increase dumping logs timeout

Increase dumping logs timeout

[EGD-6239] Fix Linux Release build on gcc-10

strncpy() was provided with size equal to a buffer size, not leaving
buffer space for a trailing zero; also sml fix.

[EGD-5743] Added phone modes popup

Implementation of phone modes window.
Minor fixes of previous approach.

[EGD-6220] Fix Calllog persistent DB entry

Date entries are stored in DB as `int`s. String version is obsolete

[EGD-6191] Fix harness call tests

* This PR provides a fix for the bug reported in [EGD-6081].
The solution adds the `tear_down`-like fixture called after the
problematic tests, that enforce focus on `ApplicationDesktop'`s
main window.
* Additionally similar solution was added to `test_auto_lock`
to restore original (30s) lock timeout.

[EGD-6081]: https://appnroll.atlassian.net/browse/EGD-6081

[EGD-5868] Add access to backup over MTP

This change adds access to backups via MTP
after backup file has been successfuly created.

[EGD-6219] Add GDB macro to print memory

Added GDB macro to print out the content
of the memory range in hex/ASCII format.

[EGD-6193] Connect Categories window with agent

Connect Categories window with agent