Replace REDLINK upload method with LINKSERVER

[multiplemonomials]

Summary of changes

Recently, NXP released their upload method, internally called Redlink, as a standalone tool, LinkServer. This tool has a much better documented API (yay!) and can be installed without also pulling in the massive MCUXpresso IDE (double yay!).

This PR updates Mbed to use LinkServer for flashing MIMXRT targets instead of Redlink.

Impact of changes

Mbed now uses the supported LinkServer application for debugging NXP devices instead of relying on MCUXpresso IDE internal tools which are not documented or intended for public consumption.

Migration actions required

People using the REDLINK upload method will need to switch to LINKSERVER. This is pretty straightforward, you just have to:

• Install LinkServer on your machine
• Pass -DUPLOAD_METHOD=LINKSERVER to CMake instead of -DUPLOAD_METHOD=REDLINK
• Update upload method configuration files (if used) to refer to LinkServer.

Documentation

Updated https://github.com/mbed-ce/mbed-os/wiki/Upload-Methods

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Pull request type

[] Patch update (Bug fix / Target update / Docs update / Test update / Refactor)
[] Feature update (New feature / Functionality change / New API)
[X] Major update (Breaking change E.g. Return code change / API behaviour change)

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Test results

[] No Tests required for this change (E.g docs only update)
[] Covered by existing mbed-os tests (Greentea or Unittest)
[X] Tests / results supplied as part of this PR

Working on running greentea tests locally using LinkServer.

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Reviewers

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[multiplemonomials]

97% tests passed, 2 tests failed out of 76

Total Test time (real) = 989.69 sec

The following tests did not run:
          8 - mbed-hal-crc (Skipped)
         10 - mbed-hal-flash-functional-tests (Skipped)
         13 - mbed-hal-mpu (Skipped)
         14 - mbed-hal-ospi (Skipped)
         16 - mbed-hal-qspi (Skipped)
         17 - mbed-hal-reset-reason (Skipped)
         19 - mbed-hal-rtc-reset (Skipped)
         43 - mbed-platform-crash-reporting (Skipped)
         53 - mbed-platform-stats-cpu (Skipped)
         54 - mbed-platform-stats-heap (Skipped)
         55 - mbed-platform-stats-sys (Skipped)
         56 - mbed-platform-stats-thread (Skipped)
         72 - mbed-connectivity-mbedtls-sanity (Skipped)
         74 - mbed-connectivity-nfc-eeprom (Skipped)
         76 - mbed-device_key-functionality (Skipped)

The following tests FAILED:
         27 - mbed-hal-trng (Failed)
         62 - mbed-rtos-mail (Failed)
Errors while running CTest

hal-trng always fails due to #83. mbed-rtos-mail and mbed-rtos-mutex are failing 50% of the time.

[multiplemonomials]

Verified that it works on Linux as well.

[multiplemonomials]

Going to go ahead and merge because I just deleted some unneeded files vs the prior approved version