Add commands to create, display and process an RTable

<pancake> i have implemented the RTable api so we just need to have a command like the agn/age/agg but for tables.

• Create a new table
• Add a row
• Import CSV or JSON (see https://github.com/radareorg/radare2/issues/3222, https://github.com/radareorg/radare2/issues/13763)
• Display/query the custom table

libr/util/table.c:

// TODO: to be implemented
R_API RTable *r_table_clone(RTable *t) {
	// TODO: implement
	return NULL;
}

R_API RTable *r_table_push(RTable *t) {
	// TODO: implement
	return NULL;
}

R_API RTable *r_table_pop(RTable *t) {
	// TODO: implement
	return NULL;
}

R_API void r_table_fromjson(RTable *t, const char *csv) {
	//  TODO
}

R_API void r_table_fromcsv(RTable *t, const char *csv) {
	//  TODO
}

R_API char *r_table_tohtml(RTable *t) {
	// TODO
	return NULL;
}

R_API void r_table_transpose(RTable *t) {
	// When the music stops rows will be cols and cols... rows!
}

R_API void r_table_format(RTable *t, int nth, RTableColumnType *type) {
	// change the format of a specific column
	// change imm base, decimal precission, ...
}

// to compute sum result of all the elements in a column
R_API ut64 r_table_reduce(RTable *t, int nth) {
	// When the music stops rows will be cols and cols... rows!
	return 0;
}