* Add HID report/descriptor for a new report with mouse buttons,
and x/y/wheel deltas.
* New mouse key press behavior for press/release of mouse keys.
* Add constants for HID main item values (e.g. data/array/absolute)
* Define and use constants for our HID report IDs.
Changed the endpoints code to rename the existing endpoint types to
"transport" and add the concept of "endpoint instances". A transport is
the method by which data is sent, while instances allow describing
multiple endpoints that use the same transport (e.g. bluetooth profiles)
Also added new APIs to get the total number of possible endpoint
instances and assign each instance a unique index, which can be used
for tracking separate state for each endpoint in other code files.
Aligns with the HID specification.
Usage page values were sometimes declared as uint8_t and sometimes uint16_t. This commit aligns all instances with the HID specification for consistency.
PR: #521
Added a new setting to remember the user's preferred endpoint. When both USB and
BLE are connected, the preferred endpoint will be used.
Added a new behavior to control this setting. It supports commands:
&end END_USB - Prefer USB output
&end END_BLE - Prefer BLE output
&end END_TOG - Toggle between USB and BLE
