CellularDevice_stub added

[AnttiKauppila]

Description

Unittests are broken because of missing CellularDevice_stub.
This is added in this PR.

This is only unittest related fix, but must be prioritized

Pull request type

[ X] Fix
[ ] Refactor
[ ] Target update
[ ] Functionality change
[ ] Breaking change

[AnttiKauppila]

@lorjala @jarvte Please review

[AnttiKauppila]

@0xc0170 Please label this to next patch release. We need to get this in rapidly because unittests are broken in master

[0xc0170]

Unittests are broken because of missing CellularDevice_stub

/morph build

[mbed-ci]

Build : SUCCESS

Build number : 3107
Build artifacts/logs : http://mbed-os.s3-website-eu-west-1.amazonaws.com/?prefix=builds/8176/

Triggering tests

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

[mbed-ci]

Exporter Build : SUCCESS

Build number : 2714
Build artifacts/logs : http://mbed-os.s3-website-eu-west-1.amazonaws.com/?prefix=builds/exporter/8176/

[mbed-ci]

Test : FAILURE

Build number : 2896
Test logs :http://mbed-os-logs.s3-website-us-west-1.amazonaws.com/?prefix=logs/8176/2896

[cmonr]

Hmm, that test failure does not like it was caused by the PR.

/motph test

[0xc0170]

/morph test

[mbed-ci]

Test : SUCCESS

Build number : 2904
Test logs :http://mbed-os-logs.s3-website-us-west-1.amazonaws.com/?prefix=logs/8176/2904

[AnttiKauppila]

@0xc0170 @cmonr Can you merge this?

[0xc0170]

Moved to 5.11 due to dependencies . Thanks @AnttiKauppila

[AnttiKauppila]

This is dependent on #7969.
7969 should go in first.