[#139] Rephrase 'file not found' logs shown during first run

[Eclipse-Dominator]

Fixes #139 Continued from #152

Modified warning messages to show filepath

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[Eclipse-Dominator]

While working on this, I realised that the

            initialData = new AddressBook();
        } catch (IOException e) {
            logger.warning("Problem while reading from the file " + storage.getAddressBookFilePath()
                    + ". Will be starting with an empty AddressBook");
            initialData = new AddressBook();
        }

and

            initializedPrefs = new UserPrefs();
        } catch (IOException e) {
            logger.warning("Problem while reading from the file " + prefsFilePath
                    + ". Will be starting with an empty AddressBook");
            initializedPrefs = new UserPrefs();
        }

is unnecessary as the actual implementation of the methods used in the try block already handles the IO Exception, I will link a separate issue here #167

[Eclipse-Dominator]

use #170