Support unlimited number/address aliases in [alias] section of ini file

Add support for an unlimited number of dial string (e.g. phone number) aliases in the [alias] section of the read .ini file. While the AT&Z, ATDSn support for stored numbers should work fine for the same use cases, it's limited to 20 numbers (that could be easily increased) and may be less obvious to users who it works. The [alias] aliases does not use AT commands to query/store the number aliases, just .ini file edits.

Re-read .ini file when ATZ command is received. This allows applying dynamic changes to the .ini file without re-running SVDM.

Address some memory-leaks when reading or making changes to .ini file.

Fix ATIn command results. The normal result format (from an actual modem) is:
<text>
<blank-line>
OK (or 0)