AP_Scripting: Add filesystem crc32 binding

[IamPete1]

#26157 made me realize that we only apply our checksum to the loaded scripts, those scripts could then be using modules that could be incorrectly versioned. This adds a binding for the same crc32 function we use for the scripting check sum, this allows scripts to checksum there modules if they want to.

However, I was unable to get the correct checksum because we were not initializing the pass by reference values, so the checksum did not start with 0 and the crc32 function does not zero it. This is possibly a issue else where but we have not noticed....

[IamPete1]

The brace initialization has minimal flash cost, this is the total for the PR:

Binary Name      Text [B]        Data [B]     BSS (B)        Total Flash Change [B] (%)      Flash Free After PR (B)
---------------  --------------  -----------  -------------  ----------------------------  -------------------------
ardurover        420 (+0.0258%)  0 (0.0000%)  -4 (-0.0015%)  420 (+0.0258%)                                   337180
blimp            412 (+0.0307%)  0 (0.0000%)  4 (+0.0015%)   412 (+0.0307%)                                   622744
arducopter       424 (+0.0240%)  0 (0.0000%)  0 (0.0000%)    424 (+0.0239%)                                   192820
arduplane        424 (+0.0241%)  0 (0.0000%)  0 (0.0000%)    424 (+0.0240%)                                   201136
ardusub          412 (+0.0264%)  0 (0.0000%)  4 (+0.0015%)   412 (+0.0263%)                                   400456
antennatracker   412 (+0.0313%)  0 (0.0000%)  -4 (-0.0015%)  412 (+0.0312%)                                   645620
arducopter-heli  424 (+0.0239%)  0 (0.0000%)  0 (0.0000%)    424 (+0.0238%)                                   186652