Show alternative symbol names

There might be multiple records for one address in symbol table (or other such resource). This is typical, but not unique, to ARM architecture. E.g. in [idioms.zip](https://github.com/avast-tl/retdec/files/1681550/idioms.zip) there is:
```
0000a635 g F .text 0000007a __udivsi3
0000a635 g F .text 00000000 __aeabi_uidiv
```
Right now, we use the first symbol and ignore the rest. IDA generates the following code:
```
.text:0000A634 __udivsi3
.text:0000A634 CMP R1, #0 ; Alternative name is '__aeabi_uidiv'
```
I.e. it names the object with one symbol name, but adds info about alternative names. This might be useful to both users and decompilation itself - both can be familiar with one symbol, but not the other. There might by more than one alternative name.

Generate this metadata to config database. Use them in analyses and print them as comments to RetDec outputs (disassembly, C).