bugfix: implement battery charge percentage in dive header This commit is (much) less trivial than the related 919e5cb51c92. First, rename the CCRmode attribute (corresponding to byte Ox59) of the SLogbookHeaderOSTC3. This byte (according to the hwOS interface document) does not contain any CCR related value, but it contains "battery information". Already since 2017, this byte is used from libdivecomputer to interface the charge percentage. So, its renamed from CCRmode to batteryCharge, to reflect its true purpose. Now, simply add a batteryCharge attribute to the SLogbookHeader (and see below why that is possible, without breaking things). The remaining changes are trivial to implement battery charge percentage in dive header. Caveat: do not get confused by the exact role of the individual logbook header types. SLogbookHeaderOSTC3 is the formal type of the logbook format that the OSTC4 produces. This format is supposed to identical to the format, as is used in hwOS for the series of small OSTCs. Only some values of attributes are different. For example, the OSTC4 supports VPM, so byte 0x79 (deco model used for this dive) also has a value for VPM. But the SLogbookHeader type, despite its name and structure, is *not* a true logbook header, as it includes attributes that are not available in the SLogbookHeaderOSTC3 formal header type. Signed-off-by: Jan Mulder <jan@jlmulder.nl>