v.db.connect: Replace -o flag with the standard --overwrite

[HuidaeCho]

This PR fixes #3149 by using the standard --overwrite flag.

[marisn]

I'm sorry, but this shall not pass. You should not remove a flag in non-major release.
Please add a printf with warning whenever -o is used: "The -o flag is deprecated and will be removed in future releases. Use --o instead"
To future proof the code, wrap the old -o in a macro #if GRASS_VERSION_MAJOR < 9

[landam]

@HuidaeCho It make sense to me to add --overwrite flag. On the other hand we cannot break backward compatibility in GRASS 8 releases. The -o flag could be removed in GRASS 9. I suggest to add depreciation warning that -o will be removed in GRASS 9.

[HuidaeCho]

This PR requires #3256.

[HuidaeCho]

@marisn, @landam Will this work with #3256?

[marisn]

@marisn, @landam Will this work with #3256?

Yes. I tested together with #3256 and backwards compatibility is in place.

[wenzeslaus]

Maybe a test to prove that both -o and --overwrite work? Probably using gs.run_command(...) (with flags="o" and overwrite=True) rather than the assert*() functions which rely on grass.pygrass Module interface which performs checks on its own and does not support lib/gis/renamed_options.

[landam]

I successfully tested:

v.db.connect map=voda_aoi table=VodniTok
ERROR: Use --overwrite to overwrite existing link for layer <1>

v.db.connect map=voda_aoi table=VodniTok --o
The table <VodniTok> is now part of vector map <voda_aoi> and may be
deleted or overwritten by GRASS modules

v.db.connect map=voda_aoi table=VodniTok --o
The table <VodniTok> is now part of vector map <voda_aoi> and may be
deleted or overwritten by GRASS modules

[landam]

@HuidaeCho Please feel free to merge (you have more than zero approvals)...