Fix the gas mixes for a few models.

For the Aeris Manta and Sherwood Insight, the header size should be 16
bytes smaller. Due to this mistake not only two samples were missing,
but also the byte offset for the gas mixes were wrong. This resulted in
invalid gas mixes, with oxygen percentages exceeding 100%.
Fix the date/time for the Aeris Elite T3.

Commit d414da70a42afca0096e0402a426c4ac8d2a2881 added support for a
second Aeris Elite T3 variant. But the parser wasn't updated to take
into account this second model number.
Add an option to disable the example applications.

The example applications may not always be needed. An option to disable
them might be useful.

Signed-off-by: Venkatesh Shukla <venkatesh.shukla.eee11@iitbhu.ac.in>
Remove the device specific example applications.

These device specific applications became obsolete long time ago with
the introduction of the universal application.