Update mongoose from 6.10 to 7.6

[ballle98]

There are compiler warnings seen after the Bullseye update

see https://github.com/cesanta/mongoose

[ballle98]

This may not be straight forward. Looks like in initially started with version 6.10 and there was an attempt

https://github.com/ballle98/AqualinkD/commits/master/mongoose.h

Updates for 1.2.6e included an update from 6.10 to 6.14
Updates to fix mongoose issues (v2.2.2) seems to be rolling back to 6.10

[ballle98]

here is a gist showing the initial set of differences https://gist.github.com/ballle98/a48a244d3d32fb29c87e24cc3ae8c61d

[ballle98]

Note the 6.10 version does compile. So build problems are the result of changes in mongoose from 6.10 to 7.6 one of the main issues being the definition of LOG macro

[ballle98]

Changed to make mongoose.c and .h symbolic links and comments imply update to version 6.18 (current release is now 7.10)
sfeakes@77c8e29