Update mime_types.conf configuration (#6013)

In the last months and years, the default `mime_types.conf` of rspamd has changed and it might be also useful to make some adjustments to the weight of certain file extensions.

This PR is removing all file extensions from `mime_types.conf` which are already in rspamd's default configuration at [rspamd/src/plugins/lua/mime_types.lua](https://github.com/rspamd/rspamd/blob/master/src/plugins/lua/mime_types.lua). If file extension is not present or has a different score compared to rspamd default, it is still in the list.

There are also a few major differences to certain file extensions, which might be useful to discuss and carefully adjust. For example, `.exe` files are rated very 'badly' due to high chance of being malicious, so are other extensions like `bat`, `cmd`, etc.

Current suggestion:
```lua
# Extensions that are treated as 'bad'
# Number is score multiply factor
bad_extensions = {
  apk = 4,
  appx = 4,
  appxbundle = 4,
  bat = 8,
  cab = 20,
  cmd = 8,
  com = 20,
  diagcfg = 4,
  diagpack = 4,
  dmg = 8,
  ex = 20,
  ex_ = 20,
  exe = 20,
  img = 4,
  jar = 8,
  jnlp = 8,
  js = 8,
  jse = 8,
  lnk = 20,
  mjs = 8,
  msi = 4,
  msix = 4,
  msixbundle = 4,
  ps1 = 8,
  scr = 20,
  sct = 20,
  vb = 20,
  vbe = 20,
  vbs = 20,
  vhd = 4,
  py = 4,
  reg = 8,
  scf = 8,
  vhdx = 4,
};

# Extensions that are particularly penalized for archives
bad_archive_extensions = {
  pptx = 0.5,
  docx = 0.5,
  xlsx = 0.5,
  pdf = 1.0,
  jar = 12,
  jnlp = 12,
  bat = 12,
  cmd = 12,
};

# Used to detect another archive in archive
archive_extensions = {
  tar = 1,
  ['tar.gz'] = 1,
};
```

**As a important reminder**: For all remaining and additional file extensions and score weights, please check above default rspamd configuration!