ci: fix path to check-api script

See merge request !17

Some build fixes

See merge request !16

This tests the libsoup2 build of the examples.

librest/examples/demo/demo-rest-page.c: In function ‘on_send_clicked’:
librest/examples/demo/demo-rest-page.c:498:24: error: too few arguments to function ‘soup_logger_new’
  498 |   SoupLogger *logger = soup_logger_new (SOUP_LOGGER_LOG_BODY);
      |                        ^~~~~~~~~~~~~~~
In file included from /usr/include/libsoup-2.4/libsoup/soup.h:31,
                 from librest/examples/demo/demo-rest-page.c:23:
/usr/include/libsoup-2.4/libsoup/soup-logger.h:59:13: note: declared here
   59 | SoupLogger *soup_logger_new         (SoupLoggerLogLevel  level,
      |             ^~~~~~~~~~~~~~~

../rest/rest-params.c:224: Warning: Rest: rest_params_as_string_hash_table: unknown parameter 'self' in documentation comment, should be 'params'

../rest/rest-oauth2-proxy.c: In function ‘rest_oauth2_proxy_build_authorization_url’:
/usr/include/glib-2.0/glib/glib-autocleanups.h:28:3: warning: ‘params_string’ may be used uninitialized [-Wmaybe-uninitialized]
   28 |   g_free (*pp);
      |   ^~~~~~~~~~~~
../rest/rest-oauth2-proxy.c:355:21: note: ‘params_string’ was declared here
  355 |   g_autofree gchar *params_string;
      |                     ^~~~~~~~~~~~~

../rest/rest-oauth2-proxy.c: In function ‘rest_oauth2_proxy_new_call’:
/usr/include/glib-2.0/glib/glib-autocleanups.h:28:3: warning: ‘auth’ may be used uninitialized in this function [-Wmaybe-uninitialized]
   28 |   g_free (*pp);
      |   ^~~~~~~~~~~~
../rest/rest-oauth2-proxy.c:114:21: note: ‘auth’ was declared here
  114 |   g_autofree gchar *auth;
      |                     ^~~~

Flatpak demo build

See merge request !15

Currently it has not practical use. I will rethink how to implement
this in nicer way in order to make one-request basic auths possible.

readme: add a link to the docs

See merge request !14

RestDemo flatpak build

See merge request !13

Also protect against misconfiguration of introspection and vapi as
introspection is needed for vapi generation

Generate vapi for Rest

Closes #5

See merge request !12

Modernized the codebase

See merge request !11

RestParams was implemented as HashTable. Limitations are that it did
not preserved the order of individual parameters aswell as duplicates
aren't allowed. Reworked it to a GList and introduced reference counting
and a boxed type.