Remove example update scripting from tools

[adbridge]

Description

The examples updating functionality has now been moved to the
mbed-release script and thus can be removed from here.

Pull request type

[ ] Fix
[x] Refactor
[ ] New target
[ ] Feature
[ ] Breaking change

[theotherjimmy]

Love it.

[theotherjimmy]

/morph build

[mbed-ci]

Build : SUCCESS

Build number : 1921
Build artifacts/logs : http://mbed-os.s3-website-eu-west-1.amazonaws.com/?prefix=builds/6819/

Triggering tests

/morph test
/morph uvisor-test
/morph export-build
/morph mbed2-build

[mbed-ci]

Exporter Build : SUCCESS

Build number : 1566
Build artifacts/logs : http://mbed-os.s3-website-eu-west-1.amazonaws.com/?prefix=builds/exporter/6819/

[mbed-ci]

Test : SUCCESS

Build number : 1739
Test logs :http://mbed-os-logs.s3-website-us-west-1.amazonaws.com/?prefix=logs/6819/1739